VoIP with Cell Phone

[omar.shakier]

Hello Dears.

this is my first question in this Forums, I hope i make question clear so you can fill me with answers :)

i work in a company and the company have to offices in different countries.

my question is: how we can receive a GSM phone call  from the first country and transport it over VoIP and receive it as VoIP phone call in the second country ?

as that possible ? and what is the required devices ?   

Regards.

[Jonathan Schulenberg]

You need a GSM Gateway in the first country. They aren't common in the USA where I live so hopefully someone else will chime in with a manufacturer recommendation. Saying which country might be helpful though.

A few other points to consider:

• Ensure sure the laws in both countries allow you to bypass the PSTN and route the call over VoIP. Some don't, usually the ones where the government owns or takes a cut of the telco.
• You'll need to implement QoS on the network path between the GSM Gateway and the VoIP user.
• Be mindful to keep the end-to-end (including PSTN portion) round trip delay under 150ms if at all possible. Above this the human ear can discern a delay. I'm saying this in case you're faced with a cost vs. path efficiency decision. For example, I wouldn't put a PSTN gateway on the US East coast if both the PSYN caller and VoIP user are on the US West cost. That would force a cross-continent round trip and adding a PSTN gateway on the West cost would provide a far better call experience.

[omar.shakier]

Thanks dear for your time and support 

another question: what is required from the ISP side ?

[Dennis Mink]

TRy this mob out,

http://www.topex.ro/en/products/voibridge_-_voip-gsm_gateway

they integrate quite nicely with Call Manager.

cheers

[omar.shakier]

Thanks Dear for the Reply 

is this the best in the market ? and what is the price ?

[Dennis Mink]

I dont know what the price is, you would need to reach out to the vendor, all you need at your end is a bunch of sim cards that connect to your local gsm/4g network