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New Member

Inbound FXO issue

I am having a problem making inbound calls to a site that has a Cisco 2811 with two 4-port FXO modules. When you call into this location, there is a delay of about 2-3 seconds from the time someone at this facility picks up the phone to the time the caller hears the phone stop ring and the person pick up.

I have attached the output from "debug vpm all".

Please help if you can.



Re: Inbound FXO issue

post some configuration if you can.

how many phones does this device support? how many calls in progress or busy is the router during this delay symptom?

do a 'show cpu' as well during these symptoms and see if the router is busy and what process if you can.

what codec are you using internally?

New Member

Re: Inbound FXO issue

This router only supports five (4) POTS lines with eleven (11) IP phones.

I tested this several times today and the router didn't have a single call coming in or going out.

The CPU on this router isn't being hit at all.

Internally, they are using G.711. This is a CCM enviroment, so all incoming calls are plar'd to a hunt pilot on CCM.

This location is set up the exact same way as eight (8) other branches. None of the other branches are having this issue.

Attached is the running config for this router.

New Member

Re: Inbound FXO issue

After looking at your config, I noticed you don't have preference statements on any of your voice-port configs in correlation to your trunk-group config. Is this consistent with configs from the other sites. The IOS voice docs say the following:

If more than one voice port is assigned to the same trunk group, the preference-num value determines the order by which the trunk group uses the voice ports. A preference-num value of 1 is the highest preference so that the voice port is used first; a value of 64 is the lowest preference so that the voice port is used last. If no value is entered for preference-num, the software assigns the voice port a preference of 65, which causes that voice port to be selected after all other voice ports are used.

I would try adding numbered preferences, do a sh / no sh on your voice-ports and pots dial-peers and then try rerunning some test calls.

There is also a "hunt-scheme" subcommand under your trunk group global command that you could tack on and see if it tweaks that timing issues as well.

Here is a link to the IOS 12.4 Voice Command docs:

New Member

Re: Inbound FXO issue

I don't have preference statements on any of the other routers.

I'm not having a problem making outgoing calls at all. I only have this issue on calls coming in to this location.

New Member

Re: Inbound FXO issue

I get the same issue, when user hangs up outside caller is still connected unless they hang up or press end call, also the line does not drop straight away I have tried all the disconnect config methods under voice-port but still waits about 5 seconds to hangup the call,


Re: Inbound FXO issue

I think that last issue is still disconnect supervision, you might have to get the lines changed to ground start to take care of that. For the incoming call issue, does it happen across all of the individual lines, if you dial the numbers associated to each port? We have had a few issues sort of like this, in one case we looked at the trace on the CM and there was an odd error delivering the call, only affected the one site, if we rebooted server it worked again for a while. Also, we have seen delay when one of the phones in the hunt group was set up for different busy/max calls than the others. But that was just general delay in answering, I think, not specifically that the phone had been answered already but caller did not get notified. CCM trace might tell you where the delay is.

Mary Beth

New Member

Re: Inbound FXO issue

If the outside caller hangs up, but the call still comes through the router/CCM, check with the telco. I have had many sites that required us to have the telco add a "COD" code to the telco lines. COD = Cutoff On Demand. Your telco may have a different term for this feature. Once they added this, the call was terminated within a second or so from the outside caller hanging up. This issue caused us many headaches trying to figure out why there were so many "ghost" calls coming into the receptionist. What was happening is that the caller would hear the opening greeting from Unity, then if they decided to hang up, the call still routed through the system and ended up going to the operator, but nobody was there since the outside caller had hung up.

Hope this helps! If so, please rate.