I am noticing something weird, when I have our business line connected to the UC520 and make a call from an external land line, the exteral call rings twice before the first ring by an ip-phone connected to the UC520. If I plug our business line directly into an old analog phone (not using the UC520) and make the same call from an external line, the first ring is almost instant.
Why is there a 2 ring delay when using the UC520, is this normal?
Keep in mind that some carriers may not send the CID untill the second ring, i know that here in Australia most carriers pass it through on the second ring, ocassionaly it may come through on the first ring, but that is rare.
You can do a Debug VPM signal (For PSTN) and or debug ISDN to see when the CID is being passed, this will give you a good indication on how much you can decrease the Ring in timer.
You need to keep an eye on caller ID showing up on the IP phone. Give it a shot. You can always go back.
This is normal. It takes a ring cycle for the FXO to detect activity and receive caller id (depending on the caller ID type). You can lower this by doing this command:
UC500(config-voiceport)#ring number ?
<1-10> The number of rings detected before closing loop
Remember to do a "shutdown", followed by a "no shutdown" after changes made to your voice ports.