Answerback/Who Are you? device

[VK1DSH]

Hello Folk,

I've been using a Kleinschmidt TT4 machine on I-Telex and it has been working well. However it didn't have an automatic Answerback mechanism which made it difficult for callers. To solve that problem I have added an Answerback unit which responds to a FIG/WRU code sequence. On receipt of the FIG/WRU sequence an answerback message is transmitted. The unit is inserted in the TTY current loop and stays idle until a WRU? request is received from the calling station, or either the 'WRU?' or 'Here Is' button is pressed on the local box.

The device uses an Arduino Nano and some optocouplers. The HCPL-2630 is equivalent to two 6N137 devices and many devices will work. The PLA110F photmos solid state relay came from a surplus source, but other solid state relays should work. The PLA110F has a 400V/200 mA rating. The box runs off a 6 VDC plug pack. The relay on the front end of the circuit keeps the TTY current functional if the AB/WRU box is not powered.

Attached are the Arduino sketch (in a zip file) and the schematic diagram. Please get back to me via I-Telex or email if you have any questions.

Regards

Dale
I-Telex 570418

[bambi]

I can add that Dale has been contacting me via I-TELEX and using the AWB/WRU Device and that it works well. I plan to build one for my terminals - It has been tested successfully my end with a M100 (T100) and a Teletype Model 15. Thanks so much Dale for designing this and for kindly sharing the information.