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27-01-89/TFSinfo
This website contains an archive of files for the Acorn Electron, BBC Micro, Acorn Archimedes, Commodore 16 and Commodore 64 computers, which Dominic Ford has rescued from his private collection of floppy disks and cassettes.
Some of these files were originally commercial releases in the 1980s and 1990s, but they are now widely available online. I assume that copyright over them is no longer being asserted. If you own the copyright and would like files to be removed, please contact me.
| Tape/disk: | Home » CEEFAX disks » telesoftware12.adl |
| Filename: | 27-01-89/TFSinfo |
| Read OK: | ✔ |
| File size: | 5709 bytes |
| Load address: | 0000 |
| Exec address: | 0000 |
File contents
TELETEXT SERVER SYSTEM
The system consists of three programs
1. A basic program 'TFS' which runs in the machine with the teletext adaptor
(henceforth called the SERVER)
2. A machine code routine 'code' which is *RUN by the program TFS.
3. A machine code program 'TELETEXT' which runs in the local machine
(henceforth called the CLIENT)
The server and client communicate on ports &B2, &B3, &B4 and &B5. The base
port number of &B2 is transmitted to the client in accordance with the Find
Server protocol. It is possible to write programs to communicate with the
TELETEXT-SERVER using these ports but it could be that updates of the server
software may use a different base port number, in which case such programs
will cease to work.
The TELETEXT program
This locates at &FFFF6E00 and so should not corrupt any BASIC program in the
CLIENT's memory. It will work with all versions of the BBC B, B+, MASTER and
ET. The program will also communicate with a SERVER across a bridge although
some of the headers may be lost as these are broadcast and there is no
collision detect across a bridge.
1. The first action is to open a receive block to receive a TELETEXT-SERVER's
reply to a find server request. This receive block listens on port &B1 to
all stations, as at this stage the CLIENT does not know the station number
of the SERVER.
2. The CLIENT broadcasts to all stations on port &B0 with a data field
containing 'TELETEXT' this being the name to which a TELETEXT-SERVER will
respond. The first SERVER to respond will be the one with which the CLIENT
subsequently interacts. Should more than one server be available then it
is possible to connect to a specific server by using its station number eg
*TELETEXT 2.45. You may wish to do this if you know that one server
receives a better signal than another, on the channel you wish to use.
3. The CLIENT polls the receive block until a SERVER responds or <ESCAPE> is
pressed.
4. The CLIENT reads the SERVER's reply and stores the SERVER's station and
network number. The base port number (&B2) is used to calculate the ports
for further communication. The CLIENT selects MODE 7, prints the SERVER's
station number (suppressing the network number if it is zero) and also the
version number.
5. The CLIENT opens three receive blocks. One on port &B5 (base+3) ready to
receive any page headers which arrive, one on port &B2 (base) ready to
receive any SERVER replies and one on port &B4 (base+2) to receive any
pages.
6. The CLIENT sends a request for page 1100 (the first digit indicates the
channel number). This is on port &B3 (base+1) with a control byte of &81.
The reply receive block is then polled until the SERVER responds. The
position in the queue returned by the SERVER is printed at the bottom of
the page. A new receive block for replies on port &B2 is set up. If an
error occurs then the error message is displayed at the bottom of the
screen and the page input routine is entered or if the error was a 'Bad
channel' error then the channel input routine is entered.
7. The CLIENT polls both receive blocks for a page (port &B4) and for a
header (port &B5), until one or the other receives a transmission.
8. If a page header is received then the cursor is moved to the header
position and it is printed out. An identical receive block is then set up
to replace the one which has been used.
9. If a requested page is received the first action is to test the control
byte. If this is &80 then it indicates the page has been found and is in
the receive block buffer ready to be transferred to the screen. If the
control byte is &81 then this indicates some error has occurred and that
an error message is in the receive block buffer waiting to be printed.
10. If an error has occurred then the error message is printed at the bottom
of the screen and the CLIENT program jumps to the page number input
routine to get another page number. A new receive block for a page is set
up.
11. If a page is successfully received then it is displayed. A new receive
block for a page is set up. The header receive block continues to be
polled and displayed until a key is pressed.
12. All the time the receive blocks are being polled the CLIENT program also
tests to see if a key has been pressed. If a key is pressed this is taken
to mean that you are about to request a new page. If 'C' is pressed then
the input channel routine is entered followed by the input page routine.
If <RETURN> is pressed then the last page you requested is requested
again. If 'R' is pressed the 'REVEAL' routine is called and this toggles
between revealing and concealing. If '*' is pressed then the star command
routine is entered. This allows the CLIENT to *SAVE pages etc. If any
other key is pressed the page input routine is entered.
13. The first action taken by both the channel input and page input routines
is to send a 'cancel page request' to the SERVER and then delete the
current page receive block. This means the SERVER will no longer have to
bother trying to find your last requested page. The prompt for a channel
input is 'C' and for a page input is 'P'. Both routines make use of OSWORD
0 to read a line of input and so both need to be exited by pressing
<RETURN>. A new receive page block is set up and then the new page number
is transmitted to the SERVER.
14. The escape flag is continually polled so that the CLIENT can exit at any
time by pressing <ESCAPE>. This will send a logoff instruction to the
SERVER which stops it looking for any more pages for you. All receive
blocks are deleted.
Sub-pages
One of the features of the normal use of teletext is that pages will roll so
that they are constantly updated eg. for cricket scores or pages with more
than one screen of information. An approximation to this facility is available
from the SERVER. Pressing 'S' will enable the automatic rolling of sub-pages.
This is done by a call to the SERVER which signals that the requested page
must not be sent until at least 0.5 of the cycle time has elapsed. Automatic
rolling of sub-pages can be disabled by pressing 'S' again. Enabling is
signalled by a high beep and disabling by a low beep. The rolling is disabled
whenever a new page is requested.
This implementation of sub-pages is a compromise in that as more clients use
this feature the more full will be the queues and it is for this reason
automatic rolling must be deliberately selected for every new page. It is also
not possible to guarantee that you will get the immediately following sub-page
in the sequence.
The TFS program
This program makes as full use as possible of the ATFS rom's ability to search
for several pages at once. The theoretical maximum is 20 at once but the size
of the TFS program limits this to about 10. The main problem is that it is
only possible to search for pages on one channel at a time and some way has to
be found to deal with this.
The approach adopted is to place a page request into one of 4 queues, one for
each channel. If the number of pages in a queue exceeds the maximum number of
pages for which the ATFS rom has space then a 'Channel busy' error will be
returned. This maximum number of pages is the number returned by the max users
per channel call. A record is kept of the total number of pages requested and
this is the queue position returned to the CLIENT ie this is the overall queue
position and not the position in the queue for a particular channel.
Whenever a page request is received the whole queue is checked to see if that
CLIENT (identified by the station number) has any other page requested. If
this is the case then that page is dropped from the queue. Thus it is not
possible for a CLIENT to request more than one page at once. A cancel page
request or a logoff will result in all page requests for that CLIENT being
dropped from the queue.
The way the ATFS rom works means that if you are 3rd in the queue you may
still receive your page before the CLIENT who is in 1st position. This is
probably best illustrated by example.
Suppose the following requests are issued :
Station 12 page 170 on channel 1
Station 14 page 400 on channel 4
Station 17 page 123 on channel 1
The TFS program will select channel 1 as this is the highest priority item in
the queue. When station 14's request arrives it will be stored in the queue
for channel 4. However when station 17's request arrives not only is it added
to the queue for channel 1 but a record is set up to receive the page if it is
transmitted. Suppose all these three requests arrive almost simultaneously and
at the moment the TFS program selects channel 1 the page being transmitted is
page 112. This means that station 17's page (123) will arrive before station
12's page(170). Thus station 17 will receive it's page first even though it
was 3rd in the queue. The next page to be sent will be 170 to station 12 and
station 14 will receive its page last even though it was 2nd in the queue.
This is not disaster as in fact station 12 has had no longer to wait than it
would have had anyway. What we have managed to do is also deal with station 17
as a spin-off from station 1's request.
If more than one station requests the same page then this is spotted and only
one of the ATFS records is used. This means that it is possible to have more
than the maximum number of users per channel queued if that channel is the
currently selected one.
When an ATFS record has been used the page it was looking for is remembered
and once that page has been found the record is not cleared. This means that
provided the channel is not changed this page will continue to be updated and
will be permanently available. Suppose a CLIENT requests page 171; the page is
received and then transmitted. If another CLIENT (or indeed the same one)
requests the same page then it is instantly available. This is particularly
useful if you happen to be the only CLIENT using the system as it means that
the last 10 or so pages you have requested on a given channel are not only
buffered by the TFS program, but also updated and instantly available.
The TFS program broadcasts whatever page number is currently at the top of the
screen by using the timer crossing zero event. This occurs every half second.
Overall the response time of the system is very fast although it will
obviously be slowed down if CLIENTs request non-existent pages. The cycle
times for the different channels are important to the efficiency of the TFS
program and as these times may be subject to change they have been included in
a DATA statement at the very end of the program. The first DATA statement is
the fraction of the cycle time for which the TFS program will wait before
sending a sub-page. This is currently 0.5. The second DATA statement consists
of the cycle times for the four channels in hundredths of a second. They are
currently set to 40 seconds each.
Installing the programs
1. Place 'TELETEXT' program in $.LIBRARY
2. Put 'TFS' and 'code' in a directory of their own. This might be the root
directory of a user TFS. If this user has a !BOOT file which CHAINs the
'TFS' program then the whole system can be initialised by simply typing
*I AM TFS. The machine running the TFS program must not use shadow screens
as the header is POKED in to memory at &7C00 by the ATFS Rom. The program
may run in a second processor, in which case the whole of the I/O
processor memory becomes available for buffering pages and there will be
an associated increase in performance. There is no advantage in using
HIBASIC as the pages are buffered in the I/O processor.
Compatibility with the GIS adapter under ATS+ Version 1.00
The software is compatible with the new GIS teletext adapter although as this
connects to the user port rather than the 1MHz Bus the speed of response is
slightly slower. There appears to be a problem with the routine to calculate
the checksum of a page in that the GIS Rom gets it wrong if a page header was
broadcast while performing the check. There does seem to be a problem with the
MASTER 128 and the TUBE in that the software will not work with either adapter
in this configuration. This looks like it may be a problem with the ANFS.
Writing your own software
Below is an example of a BASIC program which illustrates how to write your own
software using the SERVER protocols. Using this principle it is possible to
write programs for automatically receiving and saving pages.
Read the time from a TELETEXT server
10 osword=&FFF1:osbyte=&FFF4
20 DIM blk% &100,buff &100
30 REPEAT
40 :REM Set up receive blk for SERVER reply
50 rx_no=FNset_up_rx(&B1,0,buff,&20):REM Listen for all stations as we don't
60 :REM know the server station number
70 REPEAT
80 PROCbcast(&B0,&80,"TELETEXT") :REM Broadcast for a TELETEXT server
90 TIME=0
100 REPEAT UNTIL TIME>50 :REM Wait for a while before retrying
110 UNTIL FNpoll_rx(rx_no)>127 :REM Keep trying until a reply received
120
130 PROCread_rx(rx_no) :REM Read the receive block
140 buff?11=13 :REM Check that it really was a TELETEXT
150 UNTIL $(buff+3)="TELETEXT" :REM server which responded
160 server%=blk%!3 AND &FFFF :REM Read the server's number
170 base_port=buff?1 :REM Read the base port number
180 rx_no=FNset_up_rx(base_port,server%,buff,&20) :REM Set up a receive blk
190 REPEAT :REM for the time
200 REPEAT
210 PROCtx(&84,base_port+1,server%,buff,1) :REM Transmit request for the time
220 TIME=0 :REM Wait for a while before retrying
230 REPEAT UNTIL TIME>50
240 result%=FNpoll_tx
250 UNTIL result%=0 :REM Keep trying until transmit succeeds
260 UNTIL FNpoll_rx(rx_no)>127 :REM Keep trying until we get a reply
270 PROCread_rx(rx_no) :REM Read the receive block
280
290 buff?19=13
300 date$=$(buff+9) :REM Read the date
310 buff?9=13
320 time$=$(buff+1) :REM Read the time
330 PRINT"The time is ";time$;" on ";date$
340 END
350
360 DEFPROCbcast(p%,cb%,server$)
370 ?blk%=cb%
380 blk%?1=p%
390 blk%!2=&FFFF
400 $(blk%+4)=server$
410 X%=blk%:Y%=X% DIV 256:A%=&10
420 CALL osword
430 ENDPROC
440
450 DEFFNset_up_rx(p%,st%,b%,l%)
460 ?blk%=0
470 blk%?1=&7F
480 blk%?2=p%
490 blk%!3=st%
500 blk%!5=b%
510 blk%!9=b%+l%
520 X%=blk%:Y%=X% DIV 256:A%=&11
530 CALL osword
540 =?blk%
550
560 DEFFNpoll_rx(r%)
570 A%=&33:X%=r%
580 =USR(osbyte) AND &8000
590
600 DEFPROCread_rx(r%)
610 ?blk%=r%
620 X%=blk%:Y%=X% DIV 256:A%=&11
630 CALL osword
640 ENDPROC
650
660 DEFPROCtx(cb%,p%,st%,b%,l%)
670 ?blk%=cb%
680 blk%?1=p%
690 blk%!2=st%
700 blk%!4=b%
710 blk%!8=b%+l%
720 X%=blk%:Y%=X% DIV 256:A%=&10
730 CALL osword
740 ENDPROC
750
760 DEFFNpoll_tx
770 REPEAT
780 A%=&32
790 test%=(USR(osbyte) AND &FF00) DIV &100
800 UNTIL test%<128
810 =test%
SERVER Extensions
As you will find in the protocols section of this article a further
non-teletext related call has been included in the SERVER. This call returns
the value of the analogue ports. This means various devices can be attached to
the analogue port of the SERVER and can be sampled from anywhere on the
network. We are using this to monitor the outside temperature.
TELETEXT SERVER PROTOCOLS
All communications between teleserver and client are conducted on ports
base-base+3 (currently &B2-&B5). Transmissions from client to server are on
port &B3 and replies from the server are on port &B2. Port &B5 is reserved for
broadcasting the current page number being picked up by the server and port
&B4 is used for transmitting the page itself.
It is necessary to use four ports because the client may wish to have three
receive blocks open at the same time. One to continually update the page
header, one to request other information and one to receive the page itself.
The page currently being received is broadcast on port &B5 and consists of 4
bytes:
Byte 1 Channel number in ASCII
Bytes 2-4 Page number in ASCII
All transmissions to the teleserver will result in a reply being sent. The
teleserver gives up if a 'Not listening' error occurs 5 times. There are two
standard forms of reply.
a) If an error has occurred (eg you have requested a silly page number or
channel number) then the first byte of the reply data will be an error
number and the following bytes will be an error message terminated by a
carriage return.
b) If no error has occurred the first byte of the reply data will be zero and
the subsequent bytes will be dependent on the call issued.
read teleserver version number
1/client to teleserver
port &B3
control byte &80
data nil
2/teleserver to client
port &B2
control byte &80
data 0 or error number
data+1 version number as character string terminated by carriage
return.
issue page request
1/client to teleserver
port &B3
control byte &81
data channel number in ASCII
data+1-data+3 page number in ASCII
2/teleserver to client
port &B2
control byte &81
data 0 or error number
data+1 position in queue
cancel page request
1/client to teleserver
port &B3
control byte &82
data nil
2/teleserver to client
port &B2
control byte &82
data 0 or error number
data+1 nil
read max users per channel
1/client to teleserver
port &B3
control byte &83
data nil
2/teleserver to client
port &B2
control byte &83
data 0 or error number
data+1 max users
read date and time
1/client to teleserver
port &B3
control byte &84
data nil
2/teleserver to client
port &B2
control byte &84
data 0 or error number
data+1 time and date in ASCII (HH:MM:SSDD/MM/YYYY)
logoff
1/client to teleserver
port &B3
control byte &85
data nil
2/teleserver to client
port &B2
control byte &85
data 0 or error number
data+1 nil
page request with time delay
1/client to teleserver
port &B3
control byte &86
data channel number in ASCII
data+1-data+3 page number in ASCII
2/teleserver to client
port &B2
control byte &86
data 0 or error number
data+1 position in queue
request port value
1/client to teleserver
port &B3
control byte &87
data port number in range 0 to 3
2/teleserver to client
port &B2
control byte &87
data 0 or error number
data+1-data+2 port value
Reception of the teletext page
The teleserver sends the page on port &B4. The control byte will be &80 if no
error has occurred otherwise the control byte will be &81. The only error that
will occur will be a 'Timed out' error ie you have probably asked for a
non-existent page.
The data in the receive block buffer will be the page requested if there is no
error, otherwise the data will be an error message terminated by a carriage
return.If you successfully receive a page then locations &3FE and &3FF into
the receive block buffer will contain the sub page number in BCD format. &3FE
contains the hi-byte and &3FF contains the lo-byte
========================================================
ERROR NUMBERS
Possible error numbers are :
1 Bad page number
2 Bad channel
3 Channel busy
4 Time unavailable
5 Bad port
If an error is received then an error message terminated by a carriage return
will be returned in data+1.
The SERVER's receive buffer is &50 bytes.
The SERVER transmits a block of &400 bytes on port &B3 when transmitting a
page. It transmits a block of &20 bytes in all other cases.
-------------------------------
Logging on to the server
Client to Server
port &B0
control byte &80
Data The string TELETEXT as standard ASCII (the server type)
Server to Client
port &B1
control byte &80
Data 0 or error number
Data+1 base port number for further exchanges
Data+2 binary verison number of the server software
Data+3 Server type (8 chars, format as for Client to Server)
Data+11 Length of server name (=0 if not present)
Data+12 Server name (optional)
Data+12+NameLen Server type dependant OR error string
The length of the receive block buffer needed to receive this response from
the server will not exceed &20 bytes.
00000000 0d 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 |. | 00000010 20 20 20 20 20 20 20 20 20 20 20 20 20 54 45 4c | TEL| 00000020 45 54 45 58 54 20 53 45 52 56 45 52 20 53 59 53 |ETEXT SERVER SYS| 00000030 54 45 4d 20 0d 20 0d 54 68 65 20 73 79 73 74 65 |TEM . .The syste| 00000040 6d 20 63 6f 6e 73 69 73 74 73 20 6f 66 20 74 68 |m consists of th| 00000050 72 65 65 20 70 72 6f 67 72 61 6d 73 20 0d 20 0d |ree programs . .| 00000060 31 2e 20 20 41 20 62 61 73 69 63 20 70 72 6f 67 |1. A basic prog| 00000070 72 61 6d 20 27 54 46 53 27 20 77 68 69 63 68 20 |ram 'TFS' which | 00000080 72 75 6e 73 20 69 6e 20 74 68 65 20 6d 61 63 68 |runs in the mach| 00000090 69 6e 65 20 77 69 74 68 20 74 68 65 20 74 65 6c |ine with the tel| 000000a0 65 74 65 78 74 20 20 61 64 61 70 74 6f 72 20 0d |etext adaptor .| 000000b0 20 20 20 20 28 68 65 6e 63 65 66 6f 72 74 68 20 | (henceforth | 000000c0 63 61 6c 6c 65 64 20 74 68 65 20 53 45 52 56 45 |called the SERVE| 000000d0 52 29 20 0d 32 2e 20 20 41 20 6d 61 63 68 69 6e |R) .2. A machin| 000000e0 65 20 63 6f 64 65 20 72 6f 75 74 69 6e 65 20 27 |e code routine '| 000000f0 63 6f 64 65 27 20 77 68 69 63 68 20 69 73 20 2a |code' which is *| 00000100 52 55 4e 20 62 79 20 74 68 65 20 70 72 6f 67 72 |RUN by the progr| 00000110 61 6d 20 54 46 53 2e 20 0d 33 2e 20 20 41 20 20 |am TFS. .3. A | 00000120 6d 61 63 68 69 6e 65 20 20 63 6f 64 65 20 20 70 |machine code p| 00000130 72 6f 67 72 61 6d 20 20 27 54 45 4c 45 54 45 58 |rogram 'TELETEX| 00000140 54 27 20 20 77 68 69 63 68 20 20 72 75 6e 73 20 |T' which runs | 00000150 20 69 6e 20 20 74 68 65 20 20 6c 6f 63 61 6c 20 | in the local | 00000160 6d 61 63 68 69 6e 65 20 0d 20 20 20 20 28 68 65 |machine . (he| 00000170 6e 63 65 66 6f 72 74 68 20 63 61 6c 6c 65 64 20 |nceforth called | 00000180 74 68 65 20 43 4c 49 45 4e 54 29 20 0d 20 0d 54 |the CLIENT) . .T| 00000190 68 65 20 73 65 72 76 65 72 20 61 6e 64 20 63 6c |he server and cl| 000001a0 69 65 6e 74 20 63 6f 6d 6d 75 6e 69 63 61 74 65 |ient communicate| 000001b0 20 6f 6e 20 70 6f 72 74 73 20 26 42 32 2c 20 26 | on ports &B2, &| 000001c0 42 33 2c 20 26 42 34 20 20 61 6e 64 20 20 26 42 |B3, &B4 and &B| 000001d0 35 2e 20 20 54 68 65 20 20 62 61 73 65 20 0d 70 |5. The base .p| 000001e0 6f 72 74 20 20 6e 75 6d 62 65 72 20 20 6f 66 20 |ort number of | 000001f0 20 26 42 32 20 69 73 20 74 72 61 6e 73 6d 69 74 | &B2 is transmit| 00000200 74 65 64 20 74 6f 20 74 68 65 20 63 6c 69 65 6e |ted to the clien| 00000210 74 20 69 6e 20 61 63 63 6f 72 64 61 6e 63 65 20 |t in accordance | 00000220 77 69 74 68 20 74 68 65 20 46 69 6e 64 20 0d 53 |with the Find .S| 00000230 65 72 76 65 72 20 70 72 6f 74 6f 63 6f 6c 2e 20 |erver protocol. | 00000240 49 74 20 69 73 20 20 70 6f 73 73 69 62 6c 65 20 |It is possible | 00000250 74 6f 20 77 72 69 74 65 20 70 72 6f 67 72 61 6d |to write program| 00000260 73 20 20 74 6f 20 20 63 6f 6d 6d 75 6e 69 63 61 |s to communica| 00000270 74 65 20 20 77 69 74 68 20 20 74 68 65 20 0d 54 |te with the .T| 00000280 45 4c 45 54 45 58 54 2d 53 45 52 56 45 52 20 20 |ELETEXT-SERVER | 00000290 75 73 69 6e 67 20 20 74 68 65 73 65 20 70 6f 72 |using these por| 000002a0 74 73 20 62 75 74 20 69 74 20 63 6f 75 6c 64 20 |ts but it could | 000002b0 62 65 20 74 68 61 74 20 75 70 64 61 74 65 73 20 |be that updates | 000002c0 6f 66 20 74 68 65 20 73 65 72 76 65 72 20 0d 73 |of the server .s| 000002d0 6f 66 74 77 61 72 65 20 6d 61 79 20 75 73 65 20 |oftware may use | 000002e0 61 20 64 69 66 66 65 72 65 6e 74 20 62 61 73 65 |a different base| 000002f0 20 70 6f 72 74 20 6e 75 6d 62 65 72 2c 20 69 6e | port number, in| 00000300 20 20 77 68 69 63 68 20 20 63 61 73 65 20 20 73 | which case s| 00000310 75 63 68 20 20 70 72 6f 67 72 61 6d 73 20 0d 77 |uch programs .w| 00000320 69 6c 6c 20 63 65 61 73 65 20 74 6f 20 77 6f 72 |ill cease to wor| 00000330 6b 2e 20 0d 20 20 20 20 20 20 20 20 20 20 20 20 |k. . | 00000340 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | 00000350 20 20 20 20 20 20 20 20 20 20 20 20 0d 20 20 20 | . | 00000360 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | 00000370 20 20 20 20 20 20 20 20 20 20 54 68 65 20 54 45 | The TE| 00000380 4c 45 54 45 58 54 20 70 72 6f 67 72 61 6d 20 0d |LETEXT program .| 00000390 20 0d 54 68 69 73 20 20 6c 6f 63 61 74 65 73 20 | .This locates | 000003a0 20 61 74 20 26 46 46 46 46 36 45 30 30 20 61 6e | at &FFFF6E00 an| 000003b0 64 20 73 6f 20 73 68 6f 75 6c 64 20 6e 6f 74 20 |d so should not | 000003c0 63 6f 72 72 75 70 74 20 61 6e 79 20 42 41 53 49 |corrupt any BASI| 000003d0 43 20 70 72 6f 67 72 61 6d 20 69 6e 20 74 68 65 |C program in the| 000003e0 20 0d 43 4c 49 45 4e 54 27 73 20 6d 65 6d 6f 72 | .CLIENT's memor| 000003f0 79 2e 20 49 74 20 77 69 6c 6c 20 77 6f 72 6b 20 |y. It will work | 00000400 77 69 74 68 20 61 6c 6c 20 76 65 72 73 69 6f 6e |with all version| 00000410 73 20 6f 66 20 74 68 65 20 42 42 43 20 42 2c 20 |s of the BBC B, | 00000420 42 2b 2c 20 20 4d 41 53 54 45 52 20 20 61 6e 64 |B+, MASTER and| 00000430 20 0d 45 54 2e 20 20 54 68 65 20 20 70 72 6f 67 | .ET. The prog| 00000440 72 61 6d 20 77 69 6c 6c 20 61 6c 73 6f 20 63 6f |ram will also co| 00000450 6d 6d 75 6e 69 63 61 74 65 20 77 69 74 68 20 61 |mmunicate with a| 00000460 20 53 45 52 56 45 52 20 61 63 72 6f 73 73 20 61 | SERVER across a| 00000470 20 62 72 69 64 67 65 20 61 6c 74 68 6f 75 67 68 | bridge although| 00000480 20 0d 73 6f 6d 65 20 6f 66 20 74 68 65 20 68 65 | .some of the he| 00000490 61 64 65 72 73 20 6d 61 79 20 62 65 20 6c 6f 73 |aders may be los| 000004a0 74 20 20 61 73 20 20 74 68 65 73 65 20 20 61 72 |t as these ar| 000004b0 65 20 20 62 72 6f 61 64 63 61 73 74 20 20 61 6e |e broadcast an| 000004c0 64 20 20 74 68 65 72 65 20 20 69 73 20 20 6e 6f |d there is no| 000004d0 20 0d 63 6f 6c 6c 69 73 69 6f 6e 20 64 65 74 65 | .collision dete| 000004e0 63 74 20 61 63 72 6f 73 73 20 61 20 62 72 69 64 |ct across a brid| 000004f0 67 65 2e 20 0d 20 0d 20 0d 31 2e 20 20 54 68 65 |ge. . . .1. The| 00000500 20 66 69 72 73 74 20 61 63 74 69 6f 6e 20 69 73 | first action is| 00000510 20 74 6f 20 6f 70 65 6e 20 61 20 72 65 63 65 69 | to open a recei| 00000520 76 65 20 62 6c 6f 63 6b 20 74 6f 20 72 65 63 65 |ve block to rece| 00000530 69 76 65 20 61 20 54 45 4c 45 54 45 58 54 2d 53 |ive a TELETEXT-S| 00000540 45 52 56 45 52 27 73 20 0d 20 20 20 20 72 65 70 |ERVER's . rep| 00000550 6c 79 20 74 6f 20 61 20 66 69 6e 64 20 73 65 72 |ly to a find ser| 00000560 76 65 72 20 72 65 71 75 65 73 74 2e 20 54 68 69 |ver request. Thi| 00000570 73 20 72 65 63 65 69 76 65 20 62 6c 6f 63 6b 20 |s receive block | 00000580 6c 69 73 74 65 6e 73 20 6f 6e 20 70 6f 72 74 20 |listens on port | 00000590 26 42 31 20 20 74 6f 20 0d 20 20 20 20 61 6c 6c |&B1 to . all| 000005a0 20 73 74 61 74 69 6f 6e 73 2c 20 61 73 20 61 74 | stations, as at| 000005b0 20 74 68 69 73 20 73 74 61 67 65 20 74 68 65 20 | this stage the | 000005c0 43 4c 49 45 4e 54 20 64 6f 65 73 20 6e 6f 74 20 |CLIENT does not | 000005d0 6b 6e 6f 77 20 74 68 65 20 73 74 61 74 69 6f 6e |know the station| 000005e0 20 6e 75 6d 62 65 72 20 0d 20 20 20 20 6f 66 20 | number . of | 000005f0 74 68 65 20 53 45 52 56 45 52 2e 20 0d 20 0d 32 |the SERVER. . .2| 00000600 2e 20 20 54 68 65 20 43 4c 49 45 4e 54 20 62 72 |. The CLIENT br| 00000610 6f 61 64 63 61 73 74 73 20 74 6f 20 61 6c 6c 20 |oadcasts to all | 00000620 73 74 61 74 69 6f 6e 73 20 20 6f 6e 20 20 70 6f |stations on po| 00000630 72 74 20 20 26 42 30 20 20 77 69 74 68 20 20 61 |rt &B0 with a| 00000640 20 20 64 61 74 61 20 20 66 69 65 6c 64 20 0d 20 | data field . | 00000650 20 20 20 63 6f 6e 74 61 69 6e 69 6e 67 20 20 27 | containing '| 00000660 54 45 4c 45 54 45 58 54 27 20 74 68 69 73 20 62 |TELETEXT' this b| 00000670 65 69 6e 67 20 74 68 65 20 6e 61 6d 65 20 74 6f |eing the name to| 00000680 20 77 68 69 63 68 20 61 20 54 45 4c 45 54 45 58 | which a TELETEX| 00000690 54 2d 53 45 52 56 45 52 20 77 69 6c 6c 20 0d 20 |T-SERVER will . | 000006a0 20 20 20 72 65 73 70 6f 6e 64 2e 20 54 68 65 20 | respond. The | 000006b0 66 69 72 73 74 20 53 45 52 56 45 52 20 74 6f 20 |first SERVER to | 000006c0 72 65 73 70 6f 6e 64 20 77 69 6c 6c 20 62 65 20 |respond will be | 000006d0 74 68 65 20 6f 6e 65 20 77 69 74 68 20 77 68 69 |the one with whi| 000006e0 63 68 20 74 68 65 20 43 4c 49 45 4e 54 20 0d 20 |ch the CLIENT . | 000006f0 20 20 20 73 75 62 73 65 71 75 65 6e 74 6c 79 20 | subsequently | 00000700 20 69 6e 74 65 72 61 63 74 73 2e 20 20 53 68 6f | interacts. Sho| 00000710 75 6c 64 20 6d 6f 72 65 20 74 68 61 6e 20 6f 6e |uld more than on| 00000720 65 20 73 65 72 76 65 72 20 62 65 20 61 76 61 69 |e server be avai| 00000730 6c 61 62 6c 65 20 74 68 65 6e 20 69 74 20 0d 20 |lable then it . | 00000740 20 20 20 69 73 20 70 6f 73 73 69 62 6c 65 20 74 | is possible t| 00000750 6f 20 63 6f 6e 6e 65 63 74 20 74 6f 20 61 20 73 |o connect to a s| 00000760 70 65 63 69 66 69 63 20 73 65 72 76 65 72 20 62 |pecific server b| 00000770 79 20 75 73 69 6e 67 20 69 74 73 20 73 74 61 74 |y using its stat| 00000780 69 6f 6e 20 6e 75 6d 62 65 72 20 65 67 20 0d 20 |ion number eg . | 00000790 20 20 20 2a 54 45 4c 45 54 45 58 54 20 20 32 2e | *TELETEXT 2.| 000007a0 34 35 2e 20 20 59 6f 75 20 20 6d 61 79 20 20 77 |45. You may w| 000007b0 69 73 68 20 20 74 6f 20 20 64 6f 20 20 74 68 69 |ish to do thi| 000007c0 73 20 69 66 20 79 6f 75 20 6b 6e 6f 77 20 74 68 |s if you know th| 000007d0 61 74 20 6f 6e 65 20 73 65 72 76 65 72 20 0d 20 |at one server . | 000007e0 20 20 20 72 65 63 65 69 76 65 73 20 61 20 62 65 | receives a be| 000007f0 74 74 65 72 20 73 69 67 6e 61 6c 20 74 68 61 6e |tter signal than| 00000800 20 61 6e 6f 74 68 65 72 2c 20 6f 6e 20 74 68 65 | another, on the| 00000810 20 63 68 61 6e 6e 65 6c 20 79 6f 75 20 77 69 73 | channel you wis| 00000820 68 20 74 6f 20 75 73 65 2e 20 0d 20 0d 33 2e 20 |h to use. . .3. | 00000830 20 54 68 65 20 43 4c 49 45 4e 54 20 70 6f 6c 6c | The CLIENT poll| 00000840 73 20 74 68 65 20 72 65 63 65 69 76 65 20 62 6c |s the receive bl| 00000850 6f 63 6b 20 75 6e 74 69 6c 20 61 20 53 45 52 56 |ock until a SERV| 00000860 45 52 20 72 65 73 70 6f 6e 64 73 20 6f 72 20 3c |ER responds or <| 00000870 45 53 43 41 50 45 3e 20 20 69 73 20 0d 20 20 20 |ESCAPE> is . | 00000880 20 70 72 65 73 73 65 64 2e 20 0d 20 0d 34 2e 20 | pressed. . .4. | 00000890 20 54 68 65 20 20 43 4c 49 45 4e 54 20 20 72 65 | The CLIENT re| 000008a0 61 64 73 20 20 74 68 65 20 53 45 52 56 45 52 27 |ads the SERVER'| 000008b0 73 20 72 65 70 6c 79 20 61 6e 64 20 73 74 6f 72 |s reply and stor| 000008c0 65 73 20 74 68 65 20 53 45 52 56 45 52 27 73 20 |es the SERVER's | 000008d0 73 74 61 74 69 6f 6e 20 61 6e 64 20 0d 20 20 20 |station and . | 000008e0 20 6e 65 74 77 6f 72 6b 20 6e 75 6d 62 65 72 2e | network number.| 000008f0 20 54 68 65 20 62 61 73 65 20 70 6f 72 74 20 6e | The base port n| 00000900 75 6d 62 65 72 20 28 26 42 32 29 20 69 73 20 75 |umber (&B2) is u| 00000910 73 65 64 20 74 6f 20 63 61 6c 63 75 6c 61 74 65 |sed to calculate| 00000920 20 74 68 65 20 20 70 6f 72 74 73 20 0d 20 20 20 | the ports . | 00000930 20 66 6f 72 20 20 66 75 72 74 68 65 72 20 63 6f | for further co| 00000940 6d 6d 75 6e 69 63 61 74 69 6f 6e 2e 20 54 68 65 |mmunication. The| 00000950 20 43 4c 49 45 4e 54 20 73 65 6c 65 63 74 73 20 | CLIENT selects | 00000960 4d 4f 44 45 20 37 2c 20 70 72 69 6e 74 73 20 74 |MODE 7, prints t| 00000970 68 65 20 53 45 52 56 45 52 27 73 20 0d 20 20 20 |he SERVER's . | 00000980 20 73 74 61 74 69 6f 6e 20 6e 75 6d 62 65 72 20 | station number | 00000990 28 73 75 70 70 72 65 73 73 69 6e 67 20 74 68 65 |(suppressing the| 000009a0 20 6e 65 74 77 6f 72 6b 20 6e 75 6d 62 65 72 20 | network number | 000009b0 69 66 20 69 74 20 69 73 20 7a 65 72 6f 29 20 61 |if it is zero) a| 000009c0 6e 64 20 61 6c 73 6f 20 74 68 65 20 0d 20 20 20 |nd also the . | 000009d0 20 76 65 72 73 69 6f 6e 20 6e 75 6d 62 65 72 2e | version number.| 000009e0 20 0d 20 0d 35 2e 20 20 54 68 65 20 20 43 4c 49 | . .5. The CLI| 000009f0 45 4e 54 20 20 6f 70 65 6e 73 20 74 68 72 65 65 |ENT opens three| 00000a00 20 72 65 63 65 69 76 65 20 62 6c 6f 63 6b 73 2e | receive blocks.| 00000a10 20 4f 6e 65 20 6f 6e 20 70 6f 72 74 20 26 42 35 | One on port &B5| 00000a20 20 28 62 61 73 65 2b 33 29 20 72 65 61 64 79 20 | (base+3) ready | 00000a30 74 6f 20 0d 20 20 20 20 72 65 63 65 69 76 65 20 |to . receive | 00000a40 61 6e 79 20 70 61 67 65 20 68 65 61 64 65 72 73 |any page headers| 00000a50 20 77 68 69 63 68 20 61 72 72 69 76 65 2c 20 6f | which arrive, o| 00000a60 6e 65 20 6f 6e 20 70 6f 72 74 20 20 26 42 32 20 |ne on port &B2 | 00000a70 20 28 62 61 73 65 29 20 20 72 65 61 64 79 20 20 | (base) ready | 00000a80 74 6f 20 0d 20 20 20 20 72 65 63 65 69 76 65 20 |to . receive | 00000a90 20 61 6e 79 20 20 53 45 52 56 45 52 20 20 72 65 | any SERVER re| 00000aa0 70 6c 69 65 73 20 20 61 6e 64 20 6f 6e 65 20 6f |plies and one o| 00000ab0 6e 20 70 6f 72 74 20 26 42 34 20 28 62 61 73 65 |n port &B4 (base| 00000ac0 2b 32 29 20 74 6f 20 72 65 63 65 69 76 65 20 61 |+2) to receive a| 00000ad0 6e 79 20 0d 20 20 20 20 70 61 67 65 73 2e 20 0d |ny . pages. .| 00000ae0 20 0d 36 2e 20 20 54 68 65 20 43 4c 49 45 4e 54 | .6. The CLIENT| 00000af0 20 73 65 6e 64 73 20 61 20 72 65 71 75 65 73 74 | sends a request| 00000b00 20 66 6f 72 20 70 61 67 65 20 31 31 30 30 20 28 | for page 1100 (| 00000b10 74 68 65 20 66 69 72 73 74 20 20 64 69 67 69 74 |the first digit| 00000b20 20 20 69 6e 64 69 63 61 74 65 73 20 20 74 68 65 | indicates the| 00000b30 20 0d 20 20 20 20 63 68 61 6e 6e 65 6c 20 20 6e | . channel n| 00000b40 75 6d 62 65 72 29 2e 20 54 68 69 73 20 69 73 20 |umber). This is | 00000b50 6f 6e 20 70 6f 72 74 20 26 42 33 20 28 62 61 73 |on port &B3 (bas| 00000b60 65 2b 31 29 20 77 69 74 68 20 61 20 63 6f 6e 74 |e+1) with a cont| 00000b70 72 6f 6c 20 62 79 74 65 20 6f 66 20 26 38 31 2e |rol byte of &81.| 00000b80 20 0d 20 20 20 20 54 68 65 20 72 65 70 6c 79 20 | . The reply | 00000b90 72 65 63 65 69 76 65 20 62 6c 6f 63 6b 20 69 73 |receive block is| 00000ba0 20 74 68 65 6e 20 70 6f 6c 6c 65 64 20 20 75 6e | then polled un| 00000bb0 74 69 6c 20 20 74 68 65 20 20 53 45 52 56 45 52 |til the SERVER| 00000bc0 20 20 72 65 73 70 6f 6e 64 73 2e 20 20 54 68 65 | responds. The| 00000bd0 20 0d 20 20 20 20 70 6f 73 69 74 69 6f 6e 20 20 | . position | 00000be0 69 6e 20 20 74 68 65 20 71 75 65 75 65 20 72 65 |in the queue re| 00000bf0 74 75 72 6e 65 64 20 62 79 20 74 68 65 20 53 45 |turned by the SE| 00000c00 52 56 45 52 20 69 73 20 70 72 69 6e 74 65 64 20 |RVER is printed | 00000c10 61 74 20 74 68 65 20 62 6f 74 74 6f 6d 20 6f 66 |at the bottom of| 00000c20 20 0d 20 20 20 20 74 68 65 20 70 61 67 65 2e 20 | . the page. | 00000c30 41 20 6e 65 77 20 72 65 63 65 69 76 65 20 62 6c |A new receive bl| 00000c40 6f 63 6b 20 66 6f 72 20 72 65 70 6c 69 65 73 20 |ock for replies | 00000c50 6f 6e 20 70 6f 72 74 20 26 42 32 20 69 73 20 20 |on port &B2 is | 00000c60 73 65 74 20 20 75 70 2e 20 20 49 66 20 20 61 6e |set up. If an| 00000c70 20 0d 20 20 20 20 65 72 72 6f 72 20 20 6f 63 63 | . error occ| 00000c80 75 72 73 20 20 74 68 65 6e 20 20 74 68 65 20 20 |urs then the | 00000c90 65 72 72 6f 72 20 20 6d 65 73 73 61 67 65 20 69 |error message i| 00000ca0 73 20 64 69 73 70 6c 61 79 65 64 20 61 74 20 74 |s displayed at t| 00000cb0 68 65 20 62 6f 74 74 6f 6d 20 6f 66 20 74 68 65 |he bottom of the| 00000cc0 20 0d 20 20 20 20 73 63 72 65 65 6e 20 61 6e 64 | . screen and| 00000cd0 20 74 68 65 20 70 61 67 65 20 69 6e 70 75 74 20 | the page input | 00000ce0 72 6f 75 74 69 6e 65 20 69 73 20 65 6e 74 65 72 |routine is enter| 00000cf0 65 64 20 6f 72 20 69 66 20 74 68 65 20 65 72 72 |ed or if the err| 00000d00 6f 72 20 20 77 61 73 20 20 61 20 20 27 42 61 64 |or was a 'Bad| 00000d10 20 0d 20 20 20 20 63 68 61 6e 6e 65 6c 27 20 65 | . channel' e| 00000d20 72 72 6f 72 20 74 68 65 6e 20 74 68 65 20 63 68 |rror then the ch| 00000d30 61 6e 6e 65 6c 20 69 6e 70 75 74 20 72 6f 75 74 |annel input rout| 00000d40 69 6e 65 20 69 73 20 65 6e 74 65 72 65 64 2e 20 |ine is entered. | 00000d50 0d 20 0d 37 2e 20 20 54 68 65 20 20 43 4c 49 45 |. .7. The CLIE| 00000d60 4e 54 20 20 70 6f 6c 6c 73 20 20 62 6f 74 68 20 |NT polls both | 00000d70 20 72 65 63 65 69 76 65 20 20 62 6c 6f 63 6b 73 | receive blocks| 00000d80 20 20 66 6f 72 20 61 20 70 61 67 65 20 28 70 6f | for a page (po| 00000d90 72 74 20 26 42 34 29 20 61 6e 64 20 66 6f 72 20 |rt &B4) and for | 00000da0 61 20 0d 20 20 20 20 68 65 61 64 65 72 20 28 70 |a . header (p| 00000db0 6f 72 74 20 26 42 35 29 2c 20 75 6e 74 69 6c 20 |ort &B5), until | 00000dc0 6f 6e 65 20 6f 72 20 74 68 65 20 6f 74 68 65 72 |one or the other| 00000dd0 20 72 65 63 65 69 76 65 73 20 61 20 74 72 61 6e | receives a tran| 00000de0 73 6d 69 73 73 69 6f 6e 2e 20 0d 20 0d 38 2e 20 |smission. . .8. | 00000df0 20 49 66 20 61 20 70 61 67 65 20 68 65 61 64 65 | If a page heade| 00000e00 72 20 69 73 20 72 65 63 65 69 76 65 64 20 74 68 |r is received th| 00000e10 65 6e 20 20 74 68 65 20 20 63 75 72 73 6f 72 20 |en the cursor | 00000e20 20 69 73 20 20 6d 6f 76 65 64 20 20 74 6f 20 20 | is moved to | 00000e30 74 68 65 20 20 68 65 61 64 65 72 20 0d 20 20 20 |the header . | 00000e40 20 70 6f 73 69 74 69 6f 6e 20 20 61 6e 64 20 69 | position and i| 00000e50 74 20 69 73 20 70 72 69 6e 74 65 64 20 6f 75 74 |t is printed out| 00000e60 2e 20 41 6e 20 69 64 65 6e 74 69 63 61 6c 20 72 |. An identical r| 00000e70 65 63 65 69 76 65 20 62 6c 6f 63 6b 20 69 73 20 |eceive block is | 00000e80 74 68 65 6e 20 73 65 74 20 75 70 20 0d 20 20 20 |then set up . | 00000e90 20 74 6f 20 72 65 70 6c 61 63 65 20 74 68 65 20 | to replace the | 00000ea0 6f 6e 65 20 77 68 69 63 68 20 68 61 73 20 62 65 |one which has be| 00000eb0 65 6e 20 75 73 65 64 2e 20 0d 20 0d 39 2e 20 20 |en used. . .9. | 00000ec0 49 66 20 61 20 72 65 71 75 65 73 74 65 64 20 70 |If a requested p| 00000ed0 61 67 65 20 69 73 20 72 65 63 65 69 76 65 64 20 |age is received | 00000ee0 74 68 65 20 66 69 72 73 74 20 61 63 74 69 6f 6e |the first action| 00000ef0 20 69 73 20 74 6f 20 20 74 65 73 74 20 20 74 68 | is to test th| 00000f00 65 20 20 63 6f 6e 74 72 6f 6c 20 0d 20 20 20 20 |e control . | 00000f10 62 79 74 65 2e 20 20 49 66 20 20 74 68 69 73 20 |byte. 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If | 00001050 20 61 6e 20 20 65 72 72 6f 72 20 68 61 73 20 6f | an error has o| 00001060 63 63 75 72 72 65 64 20 74 68 65 6e 20 74 68 65 |ccurred then the| 00001070 20 65 72 72 6f 72 20 6d 65 73 73 61 67 65 20 69 | error message i| 00001080 73 20 70 72 69 6e 74 65 64 20 61 74 20 74 68 65 |s printed at the| 00001090 20 62 6f 74 74 6f 6d 20 0d 20 20 20 20 6f 66 20 | bottom . of | 000010a0 74 68 65 20 73 63 72 65 65 6e 20 61 6e 64 20 74 |the screen and t| 000010b0 68 65 20 43 4c 49 45 4e 54 20 20 70 72 6f 67 72 |he CLIENT progr| 000010c0 61 6d 20 20 6a 75 6d 70 73 20 20 74 6f 20 20 74 |am jumps to t| 000010d0 68 65 20 20 70 61 67 65 20 20 6e 75 6d 62 65 72 |he page number| 000010e0 20 20 69 6e 70 75 74 20 0d 20 20 20 20 72 6f 75 | input . rou| 000010f0 74 69 6e 65 20 20 74 6f 20 67 65 74 20 61 6e 6f |tine to get ano| 00001100 74 68 65 72 20 70 61 67 65 20 6e 75 6d 62 65 72 |ther page number| 00001110 2e 20 41 20 6e 65 77 20 72 65 63 65 69 76 65 20 |. A new receive | 00001120 62 6c 6f 63 6b 20 66 6f 72 20 61 20 70 61 67 65 |block for a page| 00001130 20 69 73 20 73 65 74 20 0d 20 20 20 20 75 70 2e | is set . up.| 00001140 20 0d 20 0d 31 31 2e 20 49 66 20 61 20 70 61 67 | . .11. If a pag| 00001150 65 20 69 73 20 73 75 63 63 65 73 73 66 75 6c 6c |e is successfull| 00001160 79 20 72 65 63 65 69 76 65 64 20 74 68 65 6e 20 |y received then | 00001170 69 74 20 69 73 20 20 64 69 73 70 6c 61 79 65 64 |it is displayed| 00001180 2e 20 20 41 20 20 6e 65 77 20 20 72 65 63 65 69 |. A new recei| 00001190 76 65 20 0d 20 20 20 20 62 6c 6f 63 6b 20 20 66 |ve . block f| 000011a0 6f 72 20 20 61 20 20 70 61 67 65 20 20 69 73 20 |or a page is | 000011b0 20 73 65 74 20 20 75 70 2e 20 54 68 65 20 68 65 | set up. 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All | 00001220 20 74 68 65 20 20 74 69 6d 65 20 74 68 65 20 72 | the time the r| 00001230 65 63 65 69 76 65 20 62 6c 6f 63 6b 73 20 61 72 |eceive blocks ar| 00001240 65 20 62 65 69 6e 67 20 70 6f 6c 6c 65 64 20 74 |e being polled t| 00001250 68 65 20 43 4c 49 45 4e 54 20 70 72 6f 67 72 61 |he CLIENT progra| 00001260 6d 20 61 6c 73 6f 20 0d 20 20 20 20 74 65 73 74 |m also . test| 00001270 73 20 74 6f 20 73 65 65 20 69 66 20 61 20 6b 65 |s to see if a ke| 00001280 79 20 68 61 73 20 62 65 65 6e 20 70 72 65 73 73 |y has been press| 00001290 65 64 2e 20 49 66 20 61 20 6b 65 79 20 69 73 20 |ed. 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00003550 0d 20 20 34 30 20 20 20 20 20 20 20 20 20 20 20 |. 40 | 00003560 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | 00003570 20 20 20 20 20 20 20 3a 52 45 4d 20 53 65 74 20 | :REM Set | 00003580 75 70 20 72 65 63 65 69 76 65 20 62 6c 6b 20 66 |up receive blk f| 00003590 6f 72 20 53 45 52 56 45 52 20 72 65 70 6c 79 20 |or SERVER reply | 000035a0 0d 20 20 35 30 20 72 78 5f 6e 6f 3d 46 4e 73 65 |. 50 rx_no=FNse| 000035b0 74 5f 75 70 5f 72 78 28 26 42 31 2c 30 2c 62 75 |t_up_rx(&B1,0,bu| 000035c0 66 66 2c 26 32 30 29 3a 52 45 4d 20 4c 69 73 74 |ff,&20):REM List| 000035d0 65 6e 20 66 6f 72 20 61 6c 6c 20 73 74 61 74 69 |en for all stati| 000035e0 6f 6e 73 20 61 73 20 77 65 20 64 6f 6e 27 74 20 |ons as we don't | 000035f0 0d 20 20 36 30 20 20 20 20 20 20 20 20 20 20 20 |. 60 | 00003600 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | 00003610 20 20 20 20 20 20 20 3a 52 45 4d 20 20 20 6b 6e | :REM kn| 00003620 6f 77 20 74 68 65 20 73 65 72 76 65 72 20 73 74 |ow the server st| 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000037e0 4e 54 49 4c 20 24 28 62 75 66 66 2b 33 29 3d 22 |NTIL $(buff+3)="| 000037f0 54 45 4c 45 54 45 58 54 22 20 20 20 20 20 20 20 |TELETEXT" | 00003800 3a 52 45 4d 20 20 20 73 65 72 76 65 72 20 77 68 |:REM server wh| 00003810 69 63 68 20 72 65 73 70 6f 6e 64 65 64 20 0d 20 |ich responded . | 00003820 31 36 30 20 73 65 72 76 65 72 25 3d 62 6c 6b 25 |160 server%=blk%| 00003830 21 33 20 41 4e 44 20 26 46 46 46 46 20 20 20 20 |!3 AND &FFFF | 00003840 20 20 20 20 20 3a 52 45 4d 20 52 65 61 64 20 74 | :REM Read t| 00003850 68 65 20 73 65 72 76 65 72 27 73 20 6e 75 6d 62 |he server's numb| 00003860 65 72 20 0d 20 31 37 30 20 62 61 73 65 5f 70 6f |er . 170 base_po| 00003870 72 74 3d 62 75 66 66 3f 31 20 20 20 20 20 20 20 |rt=buff?1 | 00003880 20 20 20 20 20 20 20 20 20 20 3a 52 45 4d 20 52 | :REM R| 00003890 65 61 64 20 74 68 65 20 62 61 73 65 20 70 6f 72 |ead the base por| 000038a0 74 20 6e 75 6d 62 65 72 20 0d 20 31 38 30 20 72 |t number . 180 r| 000038b0 78 5f 6e 6f 3d 46 4e 73 65 74 5f 75 70 5f 72 78 |x_no=FNset_up_rx| 000038c0 28 62 61 73 65 5f 70 6f 72 74 2c 73 65 72 76 65 |(base_port,serve| 000038d0 72 25 2c 62 75 66 66 2c 26 32 30 29 20 3a 52 45 |r%,buff,&20) :RE| 000038e0 4d 20 53 65 74 20 75 70 20 61 20 72 65 63 65 69 |M Set up a recei| 000038f0 76 65 20 62 6c 6b 20 0d 20 31 39 30 20 52 45 50 |ve blk . 190 REP| 00003900 45 41 54 20 20 20 20 20 20 20 20 20 20 20 20 20 |EAT | 00003910 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | 00003920 20 20 20 20 20 20 20 20 20 20 20 3a 52 45 4d 20 | :REM | 00003930 20 20 66 6f 72 20 74 68 65 20 74 69 6d 65 20 0d | for the time .| 00003940 20 32 30 30 20 52 45 50 45 41 54 20 0d 20 32 31 | 200 REPEAT . 21| 00003950 30 20 50 52 4f 43 74 78 28 26 38 34 2c 62 61 73 |0 PROCtx(&84,bas| 00003960 65 5f 70 6f 72 74 2b 31 2c 73 65 72 76 65 72 25 |e_port+1,server%| 00003970 2c 62 75 66 66 2c 31 29 20 3a 52 45 4d 20 54 72 |,buff,1) :REM Tr| 00003980 61 6e 73 6d 69 74 20 72 65 71 75 65 73 74 20 66 |ansmit request f| 00003990 6f 72 20 74 68 65 20 74 69 6d 65 20 0d 20 32 32 |or the time . 22| 000039a0 30 20 54 49 4d 45 3d 30 20 20 20 20 20 20 20 20 |0 TIME=0 | 000039b0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | 000039c0 20 20 20 3a 52 45 4d 20 57 61 69 74 20 66 6f 72 | :REM Wait for| 000039d0 20 61 20 77 68 69 6c 65 20 62 65 66 6f 72 65 20 | a while before | 000039e0 72 65 74 72 79 69 6e 67 20 0d 20 32 33 30 20 52 |retrying . 230 R| 000039f0 45 50 45 41 54 20 55 4e 54 49 4c 20 54 49 4d 45 |EPEAT UNTIL TIME| 00003a00 3e 35 30 20 0d 20 32 34 30 20 72 65 73 75 6c 74 |>50 . 240 result| 00003a10 25 3d 46 4e 70 6f 6c 6c 5f 74 78 20 0d 20 32 35 |%=FNpoll_tx . 25| 00003a20 30 20 55 4e 54 49 4c 20 72 65 73 75 6c 74 25 3d |0 UNTIL result%=| 00003a30 30 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 |0 | 00003a40 20 20 20 3a 52 45 4d 20 4b 65 65 70 20 74 72 79 | :REM Keep try| 00003a50 69 6e 67 20 75 6e 74 69 6c 20 74 72 61 6e 73 6d |ing until transm| 00003a60 69 74 20 73 75 63 63 65 65 64 73 20 0d 20 32 36 |it succeeds . 26| 00003a70 30 20 55 4e 54 49 4c 20 46 4e 70 6f 6c 6c 5f 72 |0 UNTIL FNpoll_r| 00003a80 78 28 72 78 5f 6e 6f 29 3e 31 32 37 20 20 20 20 |x(rx_no)>127 | 00003a90 20 20 20 3a 52 45 4d 20 4b 65 65 70 20 74 72 79 | :REM Keep try| 00003aa0 69 6e 67 20 75 6e 74 69 6c 20 77 65 20 67 65 74 |ing until we get| 00003ab0 20 61 20 72 65 70 6c 79 20 0d 20 32 37 30 20 50 | a reply . 270 P| 00003ac0 52 4f 43 72 65 61 64 5f 72 78 28 72 78 5f 6e 6f |ROCread_rx(rx_no| 00003ad0 29 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 |) | 00003ae0 3a 52 45 4d 20 52 65 61 64 20 74 68 65 20 72 65 |:REM Read the re| 00003af0 63 65 69 76 65 20 62 6c 6f 63 6b 20 0d 20 32 38 |ceive block . 28| 00003b00 30 20 20 0d 20 32 39 30 20 62 75 66 66 3f 31 39 |0 . 290 buff?19| 00003b10 3d 31 33 20 0d 20 33 30 30 20 64 61 74 65 24 3d |=13 . 300 date$=| 00003b20 24 28 62 75 66 66 2b 39 29 20 20 20 20 20 20 20 |$(buff+9) | 00003b30 20 20 20 20 20 20 20 20 20 20 20 3a 52 45 4d 20 | :REM | 00003b40 52 65 61 64 20 74 68 65 20 64 61 74 65 20 0d 20 |Read the date . | 00003b50 33 31 30 20 62 75 66 66 3f 39 3d 31 33 20 0d 20 |310 buff?9=13 . | 00003b60 33 32 30 20 74 69 6d 65 24 3d 24 28 62 75 66 66 |320 time$=$(buff| 00003b70 2b 31 29 20 20 20 20 20 20 20 20 20 20 20 20 20 |+1) | 00003b80 20 20 20 20 20 3a 52 45 4d 20 52 65 61 64 20 74 | :REM Read t| 00003b90 68 65 20 74 69 6d 65 20 0d 20 33 33 30 20 50 52 |he time . 330 PR| 00003ba0 49 4e 54 22 54 68 65 20 74 69 6d 65 20 69 73 20 |INT"The time is | 00003bb0 22 3b 74 69 6d 65 24 3b 22 20 6f 6e 20 22 3b 64 |";time$;" on ";d| 00003bc0 61 74 65 24 20 0d 20 33 34 30 20 45 4e 44 20 0d |ate$ . 340 END .| 00003bd0 20 33 35 30 20 20 0d 20 33 36 30 20 44 45 46 50 | 350 . 360 DEFP| 00003be0 52 4f 43 62 63 61 73 74 28 70 25 2c 63 62 25 2c |ROCbcast(p%,cb%,| 00003bf0 73 65 72 76 65 72 24 29 20 0d 20 33 37 30 20 3f |server$) . 370 ?| 00003c00 62 6c 6b 25 3d 63 62 25 20 0d 20 33 38 30 20 62 |blk%=cb% . 380 b| 00003c10 6c 6b 25 3f 31 3d 70 25 20 0d 20 33 39 30 20 62 |lk%?1=p% . 390 b| 00003c20 6c 6b 25 21 32 3d 26 46 46 46 46 20 0d 20 34 30 |lk%!2=&FFFF . 40| 00003c30 30 20 24 28 62 6c 6b 25 2b 34 29 3d 73 65 72 76 |0 $(blk%+4)=serv| 00003c40 65 72 24 20 0d 20 34 31 30 20 58 25 3d 62 6c 6b |er$ . 410 X%=blk| 00003c50 25 3a 59 25 3d 58 25 20 44 49 56 20 32 35 36 3a |%:Y%=X% DIV 256:| 00003c60 41 25 3d 26 31 30 20 0d 20 34 32 30 20 43 41 4c |A%=&10 . 420 CAL| 00003c70 4c 20 6f 73 77 6f 72 64 20 0d 20 34 33 30 20 45 |L osword . 430 E| 00003c80 4e 44 50 52 4f 43 20 0d 20 34 34 30 20 20 0d 20 |NDPROC . 440 . | 00003c90 34 35 30 20 44 45 46 46 4e 73 65 74 5f 75 70 5f |450 DEFFNset_up_| 00003ca0 72 78 28 70 25 2c 73 74 25 2c 62 25 2c 6c 25 29 |rx(p%,st%,b%,l%)| 00003cb0 20 0d 20 34 36 30 20 3f 62 6c 6b 25 3d 30 20 0d | . 460 ?blk%=0 .| 00003cc0 20 34 37 30 20 62 6c 6b 25 3f 31 3d 26 37 46 20 | 470 blk%?1=&7F | 00003cd0 0d 20 34 38 30 20 62 6c 6b 25 3f 32 3d 70 25 20 |. 480 blk%?2=p% | 00003ce0 0d 20 34 39 30 20 62 6c 6b 25 21 33 3d 73 74 25 |. 490 blk%!3=st%| 00003cf0 20 0d 20 35 30 30 20 62 6c 6b 25 21 35 3d 62 25 | . 500 blk%!5=b%| 00003d00 20 0d 20 35 31 30 20 62 6c 6b 25 21 39 3d 62 25 | . 510 blk%!9=b%| 00003d10 2b 6c 25 20 0d 20 35 32 30 20 58 25 3d 62 6c 6b |+l% . 520 X%=blk| 00003d20 25 3a 59 25 3d 58 25 20 44 49 56 20 32 35 36 3a |%:Y%=X% DIV 256:| 00003d30 41 25 3d 26 31 31 20 0d 20 35 33 30 20 43 41 4c |A%=&11 . 530 CAL| 00003d40 4c 20 6f 73 77 6f 72 64 20 0d 20 35 34 30 20 3d |L osword . 540 =| 00003d50 3f 62 6c 6b 25 20 0d 20 35 35 30 20 20 0d 20 35 |?blk% . 550 . 5| 00003d60 36 30 20 44 45 46 46 4e 70 6f 6c 6c 5f 72 78 28 |60 DEFFNpoll_rx(| 00003d70 72 25 29 20 0d 20 35 37 30 20 41 25 3d 26 33 33 |r%) . 570 A%=&33| 00003d80 3a 58 25 3d 72 25 20 0d 20 35 38 30 20 3d 55 53 |:X%=r% . 580 =US| 00003d90 52 28 6f 73 62 79 74 65 29 20 41 4e 44 20 26 38 |R(osbyte) AND &8| 00003da0 30 30 30 20 0d 20 35 39 30 20 20 0d 20 36 30 30 |000 . 590 . 600| 00003db0 20 44 45 46 50 52 4f 43 72 65 61 64 5f 72 78 28 | DEFPROCread_rx(| 00003dc0 72 25 29 20 0d 20 36 31 30 20 3f 62 6c 6b 25 3d |r%) . 610 ?blk%=| 00003dd0 72 25 20 0d 20 36 32 30 20 58 25 3d 62 6c 6b 25 |r% . 620 X%=blk%| 00003de0 3a 59 25 3d 58 25 20 44 49 56 20 32 35 36 3a 41 |:Y%=X% DIV 256:A| 00003df0 25 3d 26 31 31 20 0d 20 36 33 30 20 43 41 4c 4c |%=&11 . 630 CALL| 00003e00 20 6f 73 77 6f 72 64 20 0d 20 36 34 30 20 45 4e | osword . 640 EN| 00003e10 44 50 52 4f 43 20 0d 20 36 35 30 20 20 0d 20 36 |DPROC . 650 . 6| 00003e20 36 30 20 44 45 46 50 52 4f 43 74 78 28 63 62 25 |60 DEFPROCtx(cb%| 00003e30 2c 70 25 2c 73 74 25 2c 62 25 2c 6c 25 29 20 0d |,p%,st%,b%,l%) .| 00003e40 20 36 37 30 20 3f 62 6c 6b 25 3d 63 62 25 20 0d | 670 ?blk%=cb% .| 00003e50 20 36 38 30 20 62 6c 6b 25 3f 31 3d 70 25 20 0d | 680 blk%?1=p% .| 00003e60 20 36 39 30 20 62 6c 6b 25 21 32 3d 73 74 25 20 | 690 blk%!2=st% | 00003e70 0d 20 37 30 30 20 62 6c 6b 25 21 34 3d 62 25 20 |. 700 blk%!4=b% | 00003e80 0d 20 37 31 30 20 62 6c 6b 25 21 38 3d 62 25 2b |. 710 blk%!8=b%+| 00003e90 6c 25 20 0d 20 37 32 30 20 58 25 3d 62 6c 6b 25 |l% . 720 X%=blk%| 00003ea0 3a 59 25 3d 58 25 20 44 49 56 20 32 35 36 3a 41 |:Y%=X% DIV 256:A| 00003eb0 25 3d 26 31 30 20 0d 20 37 33 30 20 43 41 4c 4c |%=&10 . 730 CALL| 00003ec0 20 6f 73 77 6f 72 64 20 0d 20 37 34 30 20 45 4e | osword . 740 EN| 00003ed0 44 50 52 4f 43 20 0d 20 37 35 30 20 20 0d 20 37 |DPROC . 750 . 7| 00003ee0 36 30 20 44 45 46 46 4e 70 6f 6c 6c 5f 74 78 20 |60 DEFFNpoll_tx | 00003ef0 0d 20 37 37 30 20 52 45 50 45 41 54 20 0d 20 37 |. 770 REPEAT . 7| 00003f00 38 30 20 41 25 3d 26 33 32 20 0d 20 37 39 30 20 |80 A%=&32 . 790 | 00003f10 74 65 73 74 25 3d 28 55 53 52 28 6f 73 62 79 74 |test%=(USR(osbyt| 00003f20 65 29 20 41 4e 44 20 26 46 46 30 30 29 20 44 49 |e) AND &FF00) DI| 00003f30 56 20 26 31 30 30 20 0d 20 38 30 30 20 55 4e 54 |V &100 . 800 UNT| 00003f40 49 4c 20 74 65 73 74 25 3c 31 32 38 20 0d 20 38 |IL test%<128 . 8| 00003f50 31 30 20 3d 74 65 73 74 25 20 0d 20 0d 20 0d 20 |10 =test% . . . | 00003f60 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | 00003f70 20 20 20 20 20 20 20 20 20 20 20 20 20 53 45 52 | SER| 00003f80 56 45 52 20 45 78 74 65 6e 73 69 6f 6e 73 20 0d |VER Extensions .| 00003f90 20 0d 41 73 20 79 6f 75 20 20 77 69 6c 6c 20 20 | .As you will | 00003fa0 66 69 6e 64 20 20 69 6e 20 20 74 68 65 20 20 70 |find in the p| 00003fb0 72 6f 74 6f 63 6f 6c 73 20 20 73 65 63 74 69 6f |rotocols sectio| 00003fc0 6e 20 20 6f 66 20 20 74 68 69 73 20 20 61 72 74 |n of this art| 00003fd0 69 63 6c 65 20 20 61 20 20 66 75 72 74 68 65 72 |icle a further| 00003fe0 20 0d 6e 6f 6e 2d 74 65 6c 65 74 65 78 74 20 20 | .non-teletext | 00003ff0 72 65 6c 61 74 65 64 20 20 63 61 6c 6c 20 68 61 |related call ha| 00004000 73 20 62 65 65 6e 20 69 6e 63 6c 75 64 65 64 20 |s been included | 00004010 69 6e 20 74 68 65 20 53 45 52 56 45 52 2e 20 54 |in the SERVER. T| 00004020 68 69 73 20 63 61 6c 6c 20 72 65 74 75 72 6e 73 |his call returns| 00004030 20 0d 74 68 65 20 76 61 6c 75 65 20 6f 66 20 74 | .the value of t| 00004040 68 65 20 61 6e 61 6c 6f 67 75 65 20 70 6f 72 74 |he analogue port| 00004050 73 2e 20 54 68 69 73 20 6d 65 61 6e 73 20 76 61 |s. This means va| 00004060 72 69 6f 75 73 20 64 65 76 69 63 65 73 20 63 61 |rious devices ca| 00004070 6e 20 62 65 20 61 74 74 61 63 68 65 64 20 74 6f |n be attached to| 00004080 20 0d 74 68 65 20 20 61 6e 61 6c 6f 67 75 65 20 | .the analogue | 00004090 20 70 6f 72 74 20 20 6f 66 20 20 74 68 65 20 20 | port of the | 000040a0 53 45 52 56 45 52 20 20 61 6e 64 20 20 63 61 6e |SERVER and can| 000040b0 20 62 65 20 73 61 6d 70 6c 65 64 20 66 72 6f 6d | be sampled from| 000040c0 20 61 6e 79 77 68 65 72 65 20 6f 6e 20 74 68 65 | anywhere on the| 000040d0 20 0d 6e 65 74 77 6f 72 6b 2e 20 57 65 20 61 72 | .network. 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27-01-89/TFSinfo.m0
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.