Cisco CUCM/2951 Gateway Quick Question

[leftyx]

I had a quick question on transferring to the PSTN.

If I get an inbound call to my ext.5150 Then transfer to the PSTN DID of another ext to the desk next to me ext.248-XXX-4500. (Just for argument sake)

On my 2951 Router; I would have 3 calls correct?

1. The original inbound
2. The outbound PSTN call to 248-XXX-4500
3. The inbound call from PSTN to 4500.

It is my understanding that a transfer to the external PSTN from CUCM still is active on the Router. I just want to double check my thinking.

 

[leftyx]

Anyone care to take a stab?

 

[whykap]

The short answer is yes, you would occupy 3 channels, lines, trunks, depending on your PSTN trunking. There's things you can do to avoid that, but normally you would use three. One for each leg call.

 

[leftyx]

How could I avoid that? Would love to hear any thoughts.

 

[whykap]

Why do internal users call other internal users using their PSTN number and not their internal DN?
If that's something you can't avoid from your end users, you can create translation patterns to change the 248-XXX-4500 to 4500 (using your example), so it never hits the PSTN. That way the call stays internal even though the users dial outbound.
You would need to do this for all your internal DID's, if they are sequential it's simple.

You can also do it with certain PSTN providers as long as they support path replacement.