On the ISR router with a FXO port you can also use a command to verify voltage for the voice port. There is a Cisco document that details the command used below, it will report if there is any voltage on the fxo port in question. I used this command to remotely troubleshoot an outage report for an overhead paging system. The paging system is providing the voltage/battery. If this was a CO type line, then, again the PSTN is providing the battery, so if it is connected to the fxo, you must have voltage.

Example:

> term mon

> test voice port port# si-reg-read 29 1

>

> A value of 0x00 indicates there is no voltage being seen on the line/voice port.

> You need the terminal monitor command to see the output of this command on the screen.

homegw-220#ter mon

homegw-220#test voice port 3/0/2 si-reg-read ?

<0-200> Starting register in decimal: 0 - 200

homegw-220#test voice port 3/0/2 si-reg-read 29 ?

<1-6> Number of registers to be Read: 1 - 6

homegw-220#test voice port 3/0/2 si-reg-read 29 1

homegw-220#

Jun 18 2009 16:44:53.629 EDT:

Values read from SiLabs Codec connected to DSP 0, channel 2:

--------------------------------------------------------------

Register 29 = 0x00

Jun 18 2009 16:44:53.629 EDT: >

A value of 0x00 indicates there is no voltage being seen on the line/voice port.

To the person that rated my post an "1":

you're misusing the rating system, because the information that I gave is correct to the best of my knowledge, and given in good will.

Although relatively simple I use a "show voice port summary" and then call into the FXO line. You will see the port chaning status to ring-detected, if the status show no change, then there's nothing connected.

thanx a lot... I hadn't an analog phone to test a line, your answer is a piece of gold.

Who told that a 4 years answer would help me?

Regards