iz8dwf | Restoring the DCD AC.350.OM acoustic coupler pt. 3: RX test & going online! @iz8dwf | Uploaded December 2018 | Updated October 2024, 1 hour ago.
Restoring a DCD model AC.350.OM acoustic coupler, S/N 350/381.
Parts 1 & 2:
youtube.com/watch?v=ZAICCy4OC-8
youtube.com/watch?v=4-StGVDZzXA
Testing the RX part and finding a problem in the little microphone preamplifier board. Finally going "online" with a real phone call but, as expected, a "modern" modem gets confused by the fact that this acoustic coupler transmits continuously the Originate idle tone, so I had to learn when it was possible to switch it on during the handshake and protocol negotiation phase.
This may be a rare connection between one of the more primitive and one of the most advanced telephone modems :)
Restoring a DCD model AC.350.OM acoustic coupler, S/N 350/381.
Parts 1 & 2:
youtube.com/watch?v=ZAICCy4OC-8
youtube.com/watch?v=4-StGVDZzXA
Testing the RX part and finding a problem in the little microphone preamplifier board. Finally going "online" with a real phone call but, as expected, a "modern" modem gets confused by the fact that this acoustic coupler transmits continuously the Originate idle tone, so I had to learn when it was possible to switch it on during the handshake and protocol negotiation phase.
This may be a rare connection between one of the more primitive and one of the most advanced telephone modems :)
