Response 400 answer machine - no response

[N Cook]

Main system does not seem to recognise there is an active phone line
connected.
Should show alternately "HO" or "00" on pressing one of the buttons , just
beeps and 2 character
display stays at "o" and no activation to ring pulses.
Phone and tape sections working order - anyone any specific knowledge ?

 

[James Sweet]

Main system does not seem to recognise there is an active phone line
connected.
Should show alternately "HO" or "00" on pressing one of the buttons , just
beeps and 2 character
display stays at "o" and no activation to ring pulses.
Phone and tape sections working order - anyone any specific knowledge ?

You'll have to open it up and do some troubleshooting, once you figure
out how it detects the presence of voltage on the line you can probably
figure out why it's not detecting it. The problem is likely fairly simple.

 

[N Cook]

You'll have to open it up and do some troubleshooting, once you figure
out how it detects the presence of voltage on the line you can probably
figure out why it's not detecting it. The problem is likely fairly simple.

I'm assuming for the moment that the relay that connects
the standing DC on the phone line through to the other side
should be active when there is power to the machine and
switched to answer machine mode and active phone line
is connected so it can register an active line.
This relay and driver works if i drive it but 0 level on the only line
that connects back to the main micro so presumably an output.
The keyboard controller is signalling this main micro
when changing operational status but no drive to the relay