My apologies if I have posted in the wrong forum. I work in the service department of a two-way radio dealer and have a customer (Cab company) who has recently upgraded their phone system to incude a number of VVX300s. On their dispatch phones they use a headset connected to a Zetron TRHI, an interface that controls audio to either radio or the phone based on a hook indication, essentially a short to a ground input.
I have the pinout for the RJ9 but am still trying to find out how we can work with the hook indication. I have been told that the serial port will supply this but the documentation implies more of an "EHS". Has anyone used this kind of configuration before or can point me in the right direction?
Thank you for your assistance,
Jeff Banville
Service Department
Telequip Systems Ltd