IP Phone cannot make internal calls

[woodlodge]

Hello all

Hope someone can help...

We have Cisco 7942 IP Phones.

We can make outgoing calls.
We can receive incoming calls.
We can transfer incoming calls to other internal phones.
We cannot however make internal calls!
When we try the phone rings but no-one can hear anything.

What could it be?

Thanks in advance

[Carlo Poggiarelli]

hi.

Can you check the calling search space assigned to IP Phone's directory number?

Let me know

Regards

Carlo

[Vimal K V]

Hi woodlodge,

Could you please check whether Calling Search Space  of 7942 IP phone contains the Partition of the internal phone which you are trying to call ?

OR

You may check the call details record and check where the call is hitting now.

OR

You may run a Dialed Number Analyzer  test and check the  route of the call.

HTH,

VKV

[woodlodge]

Hi Thanks for the reply.

Just to be clear this is not just one phone.

It is ALL phones to any internal number.

I think it is more likely to be some protocol or firewall issue but have no idea how to diagnose to see what needs to be enabled on the internet gateway.

[Vimal K V]

Hi woodlodge,

Is the called party able to pick up the call successfully ?

Is this one way no audio or two way no audio issue ?

Regards,

VKV

[woodlodge]

Hi

When any party calls another internally the target handset rings but when answered neither party can here the other.

Thanks

[Vimal K V]

Hi woodlodge,

Was this call scenario working before ? or Is this a new implementation ?

Regards,

VKV

[woodlodge]

It was ok but stopped working when we changed ISP.  Hence my suspicion regarding protocols etc...

Thanks again

[Vimal K V]

Hi woodlodge,

I suggest,

1. Check the call flow using the DNA

2. Understand which endpoint/gateway/CUBE is feeding the call to PSTN

3. Run the test call and let the called party pick up the call

4. Run a command "show call active voice brief" multiple times on the PSTN exit Gateway and see packet count (incoming + outgoing ) has been increasing or not.

4. If packet count is not increasing in regular interval, check the firewall that is facing the ISP and understand whether it is blocking any RTP traffic.

Reference :: http://www.cisco.com/c/en/us/support/docs/voice/voice-quality/40309-show-call-act-voice.html

Regards,

VKV

[woodlodge]

Hi

Thank you so much foryour time and effort.

I will do this first thing  when I get into the office later and let you know how we got on.

[Vimal K V]

Hi woodlodge,

Did you make any progress ? Did you sort out the problem ?

Request you to endorse the suggestion if it helps.

Regards,

VKV

[woodlodge]

We found a fairly simple solution...
We are replacing the Cisco stations with ones that work.

Thanks anyway

[Vimal K V]

Hi woodlodge,

Thank you for sharing the information with me. Appreciate it.

You are welcome.

Regards,

VKV

[Deb760]

We have Cisco SPA504G phones doing the same thing. We can receive and make outside calls with no issue. But we cannot call internally. The calls ring to the other extension, but neither party can hear one another.

[Maren Mahoney]

First of all, I would encourage you to start a fresh post so we can help you.

The two things I can think of that would cause an issue such as you describe are codec mismatches, or routing/firewall issues. Since you say the call stays up and also because I assume all of your internal phones are in the same region, we can discount codec mismatch at least initially.

If your internal phones can call each other, and when picked up the call stays up but there is no audio, my first thought would be that for some reason you have a firewall that is blocking the RTP traffic flowing between your phones. Do you have security folks that you can ask about this?

Maren