mirrexagon / old-phone-control

Requirements

• Box that connects to computer via USB, ideally bus-powered
• Box connects on the other side to the 600-series phone connector
• USB exposes:
  • Audio class
    • Phone microphone
    • Phone speaker
    • (Think about how both voices go on one line)
• HID keyboard – outputs 0-9 from dialing
• Off-hook detection, send as button?

Notes

• Need to supply 36-48 V on the phone line?
• When off hook, resistor load is applied to drop voltage to <10 V
• Can try using an old phone-VOIP modem for a phone line simulator I can probe

Links

• https://en.m.wikipedia.org/wiki/600_series_connector
• https://goughlui.com/2017/12/22/tech-flashback-telecom-600-series-adapters-extensions/
• https://oldaustraliantelephones.weebly.com/testing-your-telephone-service.html
• https://www.cool386.com/cb_exchange/cb_exchange.html
• https://www.um.es/docencia/barzana/DIVULGACION/TELEFONIA/Funcionamiento_telefono.html
• https://www.youtube.com/watch?v=hSqoAvyqJNs
• Audio separation from line voltage: https://www.ranecommercial.com/legacy/note150.html