V.21 (Modified Analogue Card)
Verfasst: Fr 15. Mai 2020, 16:54
After some time discussing what was needed to operate the last generation of Telex machines found in the UK with Henning I ordered a modified Analogue Card.
In the UK we call this protocol SCVF (Single Channel Voice Frequency) But in more generic terms it is FSK or Frequency Shift Keying, and runs to the V.21 Protocol.
There were some initial bugs with the card that Henning quickly resolved, so I had tones to play with.
Over the past 24 hours Fred has also been very helpful in resolving a difference in the software which was stopping my machine from communicating with i-Telex - Once the tones were monitored with a soundcard based spectrum analyser, it was easy to see that the card was responding the opposite way to the machine - I -Telex was opening communication when the machine was closing the line.
Some locally induced faults during reprogramming also added confusion (I bent one of the pins on the ATMEL so it was not connecting to the socket) were resolved and the system just works!
So, once the software and hardware were working together correctly, it was just plug in the telex machine, set up the local port number, and connect to the world
Thanks must go to Fred and Henning for all their help and assistance in getting this new card to work - once the bugs were ironed out it really is the simplest card I have found on the system.
In the UK we call this protocol SCVF (Single Channel Voice Frequency) But in more generic terms it is FSK or Frequency Shift Keying, and runs to the V.21 Protocol.
There were some initial bugs with the card that Henning quickly resolved, so I had tones to play with.
Over the past 24 hours Fred has also been very helpful in resolving a difference in the software which was stopping my machine from communicating with i-Telex - Once the tones were monitored with a soundcard based spectrum analyser, it was easy to see that the card was responding the opposite way to the machine - I -Telex was opening communication when the machine was closing the line.
Some locally induced faults during reprogramming also added confusion (I bent one of the pins on the ATMEL so it was not connecting to the socket) were resolved and the system just works!
So, once the software and hardware were working together correctly, it was just plug in the telex machine, set up the local port number, and connect to the world
Thanks must go to Fred and Henning for all their help and assistance in getting this new card to work - once the bugs were ironed out it really is the simplest card I have found on the system.