What do i need

[mhen.beetseh]

 hello

I want to install an intercom voip system for my office. Will have 45 IP phones. If i purchase a 2921/k9 and SL-29-UC-K9. will that be enough? of i still have to buy something else. I already have cisco POE switches and lan in place.

Thanks

[Dennis Mink]

Do you mean a phone to phone intercom system (which call manager express supports) or like an analoug announcement system?

[mhen.beetseh]

Thank you Sir,

I mean a phone to phone intercom system.

[R0g22]

You can setup your CME Phones for intercom as well if that is what you meant. If you want to have an external system, these are usually integrated via analog. Typically FXS if the system is not externally powered or FXO if it is externally powered.

[mhen.beetseh]

Thank you Sir, 

I also want to ask, If it becomes necessary to connect out landline like E1, what will i need in addition.

Thank you.

[R0g22]

Not necessary AFAIK. Then again if you have a PBX connected to a Cisco GW via QSIG E1 tie lines, that is a different thing all together.