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Community Member

VoIP implementation on a lab

Hi, to all...

I'm a newbie to VoIP and a difficult assignment was given to me at my university...

More specifically, I have to make the following implementation...

To be able:

1. To call conventional phones from the computers of our lab

2. To get calls from a foreign country (for example England) and our Cisco 3640

router to attend the connection to a local phone...

Conserning the first issue,I want to ask this:for the PSTN connection I have to connect an RJ-11 cable from the FXO port to the conventional telephone of the lab? and what about the dial peer statements?

The second issue is way out of my lead. Any suggestions would be helpful.

I have read some Cisco books but due to that I'm inexperienced concerning cisco programming it's hard for me to implement, so I would be grateful for any suggestions&advices given.

Thanks everyone who has the patience to read my topic in advance!

Hall of Fame Super Silver

Re: VoIP implementation on a lab

What are you planning on using as your call processing agent (PBX), CallManager or CallManager Express. CallManager requires Cisco approved server (either HP or IBM), and CallManager Express is IOS based, runs on Cisco Router. I would recommand CCME for your demonstration.

You are correct as to statement one, you will need 2 dial-peers: voip and pots, read these docs for more details:

here is doc about configuring them:

As to question number 2, by plugging the FXO to the router and configuring CallManager (either one), and creating the dial-peers, you will be able to make the calls.

I am not sure what you ment by "attend the connection to a local phone", but if you mean to connect regular phone set to the router this can be achived by installing an FXS card on the router. If you mean to integrate with existing phone system, you will still need either one of the Callmanager products.

Check out this document for CCME configuration:


Community Member

Re: VoIP implementation on a lab

You do not require Cisco Callmanager or Callmanager Express. As you say this is for your lab, you can just use an analog phone, connect it to an FXS port on the router you have, terminate a POTS line on the FXO port on the router and that should solve your issue.

For configuring this, visit the following URL :

Lemme know if you have any questions

Community Member

Re: VoIP implementation on a lab

Yes, I made (I hope) the appropriate configs and I connected an analog phone to the FXS port (2/0/0) and the FXO port to (2/1/0). More specifically here are my dial-peer statements:


dial-peer voice 1984 pots

destination-pattern +1984

port 2/0/0

! (/* For the analog phone */)


dial-peer voice 2005

destination-pattern +0..........(/*10 dots */)

port 2/1/0


If you want to make outgoing calls from my university you have to first dial "0" and afterwards dial the rest of the phone number you wish (for example 2105910554-my house-a 10digit number). That means that by dialing "0" you are connected to the universitys' PBX and then it attends the call to the appropriate path through PSTN right? Unfortunatelly when i tried to call the call couldn't be done and I don't know what's wrong... And I checked that both the VICs (FXO&FXS) are enabled...

Any ideas? Thanks again!!!


Re: VoIP implementation on a lab

How have you configured you voice port 2/1/0? Meaning what type of singaling are you using to connect to the PBX.

Also I don't know if it matters but you are missing the pots keyword in the after dial-peer voice 2005

One last thing, do you need to dial a 1 before the area code? If so then you'll need 11 dots.

Community Member

Re: VoIP implementation on a lab

Concerning the FXO 2/1/0, the configuration has as follows:


voice-port 2/1/0

cptone GR

timeouts call-disconnect 0

signal groundStart


So I use groundStart signaling for connecting to the PSTN. From the FXO 2/1/0 port I connect an RJ-11 cable to the lab's telephone wall outlet. When you use a conventional analog phone to the specific outlet for outgoing calls, you have to dial "0" first and afterwards dial the rest of the telephone number (210->the area code-and the rest 7 digits of the desirable destination). So that's why I configured dial peer <2005> with the following destination pattern +0.......... (10 dots).

So what do you think? I'll attach an offhand draw...

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