Showing results for 
Search instead for 
Did you mean: 

IP Telephony in a building

Hello Everyone

I want to provide Telephony services in building with around 60 residential flats. I have option using a epbx or IP telephony

I want to know if I use IP telephony, how user will call Landline phone or mobile phones. How the call will get to the PSTN lines from broadband connection. And is it possible to have each residential flat has unique caller ID which can be used by outside world to give a call back.

And which is better approch epbx or IP Telephony. My aim is to provide cheap national international calls.


Deepak Khemani                  


Hi Deepak,

I would always prefer IP telephony over epbx.

The best product for your is CME. All of your requiremet can be fullfilled by CME.


Ronak Patel

Rate helpful posts.

Regards Ronak Patel Rate all helpful post by clicking stars below the answer.
Cisco Employee

Hi Deepak,

I'm going to take a stab at this.

First of all, neither epbx nor IPT will help in providing cheap national / international calls in India where the TRAI laws forbid any sort of toll bypass. Here are some more details on it:

Regulations of the Telecom Regulatory Authority of India (TRAI) require  that voice traffic over the enterprise data network and the Public  Switched Telephone Network (PSTN) must be strictly separated and no  mixing of calls between the two networks can occur for the purpose of  toll bypass.

The following list shows basic scenarios that are restricted (that is, not allowed):

The  call that passes through a PSTN gateway connects directly by using WAN  to a VoIP phone or VoIP PSTN gateway in a different geographic location.

If  PSTN gateway is located in India, this remains strictly restricted. If  the PSTN is in another country and a VoIP phone is in India and if  connection results in revenue loss to Indian telecom service providers,  the connection gets considered restricted.

The following list gives basic scenarios that are permitted:

Call directly between two VoIP phones in different geographic locations

Call from a VoIP phone to a PSTN gateway in the same geographic location

A call that passes through a PSTN gateway must never connect directly to  a VoIP phone or VoIP PSTN gateway in a different site or geographic  location (geolocation) through use of IP telephony.

As for the question of how the user will call landline / mobile phones, it depends on how you are providing the PSTN connectivity - FXO / E1 PRIs / etc. Considering there will be 60 residential flats, you would want each flat to have an independant phone with a dedicated DID. In that case, it makes more sense to go for a E1 PRI. However, you could even look at an ITSP such as Tata Communications, which might prove as a cheaper option in the long run, even for national / international calls possibly. But be careful about the TRAI DOs and DONTs :-) Lastly, yes it is possible to have each flat have a unique DID which can be used to call back on.





Forgot to add at the end -- go with IPT ofcourse. Like Ronak said, CME / CUE is more than enough for something like this.