I was trying to make an old Ericsson cobra phone ring to incoming calls to no avail.
At first I thought there was a problem with how I wired the ringer on the phone itself but now I'm sure there's something else at play here.
On an old-school telephone line there should be a 90 (or thereabouts) VAC ringing signal when someone is calling you which is plenty for the buzzer to do its thing.
But there's nothing showing on the scope when probing my VOIP phone line other than DC.
Not sure what's the equivalent of a ring signal on a modern line..I don't see anything when I call myself..
I tested the buzzer with an AC voltage of about 70V@20Hz and it rings so there's nothing else there preventing it to ring other than the line itself.
Is my project doomed to fail?I can talk to and hear the callee but what good is that if you don't know when you're being called.
I was looking for some kind of trigger or something but it's just DC..
Really hope that I've missed something!
Just to clear up terminology: by “VOIP phone line”, do you mean the analog phone jack of some VoIP device? If not, can you elaborate?
Assuming you do mean an analog jack on a piece of network equipment (such as your ISP-provided modem/router), please provide the model number so we can look up the specs. Maybe it’s outputting a much lower ring voltage (or current) that’s enough to trigger an electronic ringer, but not ring a mechanical bell.
(A VoIP “line” doesn’t really exist as such. It’s packet-switched, not circuit-switched, using TCP/IP and UDP, with VoIP phones typically being connected via Ethernet or Wi-Fi.)