SPA 112 reboot while calls are in progress

[vtrikola]

Hello,

How can I reboot remotely my SPA 112 while calls are in progress?

Thank you

[Dan Lukes]

No way. Calls must be disconnected first.

[vtrikola]

Thank you very much for your answer.

How can I stop calls remotely when my SPA FXS port is broken?

Do you know if the FXS ports have overload protection and if they have what the limit is?

Thank you

[Dan Lukes]

How can I stop calls remotely when my SPA FXS port is broken?

The SPA112 will queue all reboot or reconfigure requests while a call is connected - no way to order SPA112 to disconnect. Thus the other end may help you - the PBX should BYE the existing call.

Of course, power cycle will restart the unit as well (but no way to initiate it remotely).

Do you know if the FXS ports have overload protection and if they have what the limit is?

FXS port need not to have active overload protection. It's internal impedance is high enough to take even permanently shorted line with no harm.

But the overvoltage may harm the port. The SPA112 is powering the line - no one should power it. No external voltage on wire is expected. Thus if the wire is misconnected (for example into another FXS port, powered by PBX) or if there's spike induced on it (not only lightning is source of spikes, long phone line in parallel  with mains power line may be affected as well) the port may be damaged.

There's no internal lightning arrester or overvoltage protection.

You can try to restart the unit, but I suspect it will have no effect. If the FXS port is broken, it will not be recovered.

By the way, why you think the port is broken ?

If it is because the port is still in "off hook" state, then verify it's not caused by broken phone connected. Just disconnect wire from FXS port. If still 'off hook' then port is broken. If it will turn to 'on hook' state then either connected phone is broken or connecting wire is shortened somewhere. So reconnect the wire and disconnect far phone - it will allow you to distinguish those two cases.

[vtrikola]

Thank you for tha information.

We are using this adapters on highway for emergency calls and the lines are long. The FXS ports are broken all the time by overvoltage on them. What do you suggest to protect these ports?

[Dan Lukes]

Just curious - how 'long' is long here ? And which kind of wire (diameter or AWG type) are you using ? There has been two theoretic threads related to it ([1],[2]) but no one with true experience. And Cisco has never disclosed the SLIC specifications ...

What do you suggest to protect these ports?

Sorry, no personal experience here. Despite we have many installations, all of them are 'indoor'. I can offer just some notes to you. On long outdoor line both ends should have protection (if you wish to save devices on both sides). There are many "phone line protectors" available on the marked, but try to avoid the most cheap one. Not only they may not be fast enough to protect again lightning spikes and they may not be sensitive enough to protect against smaller overvoltage induced. Imperfect protector may cause line dis-balance, which in turn may cause the 50/60Hz (or other) noise induced into line on the patch become so loud to be ignored during call.

Also remember the protector on both ends require reliable grounding to work properly.

Ask an local electrician for advice in doubt.

[vtrikola]

Thank you very much for your information.

I will dome some research about what line protectors I have to use.

[smithmurphy]

I'll unearth this old thread, because I have not seen any answer for this issue.

The best way I've found to be able to reboot a SPA112 who has a line off hook is to shutdown the Ethernet port on the switch facing the SPA112. This will unregister the SIP account and force the line hook to drop.

cheers,

Murphy