What is a GSM Gateway?

A GSM Gateway is a device that can be installed onto a business telephone system / switchboard (PBX) and it functions as a link between the PBX and GSM network. The GSM Gateway device is usually connected to the trunk side of the PBX. When connected to the main line of the telephone system, the phone system can be programmed to automatically route mobile calls to that particular line or can be set up so the user has to dial a prefix or select a line key to be connected to the GSM Gateway and then the mobile number desired.

Who can benefit the most from using a GSM Gateway?

The GSM Gateway is a functional solution for companies, since it enables connection with the GSM network from the fixed phone at prices substantially lower than the ones charged for fixed network

What choice of GSM gateways are there?

The are four ways to connect a GSM Gateway to a telephone system and all of these relate to replacing the traditional fixed line service, therefore the interfaces used are the same.

1. Analogue - an analogue GSM gateway will connect to the analogue trunk port of a phone system

2. ISDN2 - an ISDN2 GSM gateway will typically provide 2 x simultaneous calls using 2 sim cards and will connect to an ISDN2 port of a telephone system.

3. ISDN30 - an ISDN30 GSM Gateway will provide 8 to 30 simultaneous calls depending upon the number of GSM engines installed in the gateway. ISDN30 / PRI GSM Gateways can be connected to a dedicated ISDN30 trunk card of a telephone system or can be utilised in-line between the ISDN30 interface on the PBX and the ISDN network. Where a GSM Gateway is used in-line between the PBX and ISDN network the units can be programmed to automatically route mobile calls through the GSM engines and pass through non mobile calls to the ISDN network - this is particularly useful if there is no capacity for an extra ISDN30 trunk card in the PBX.

4. IP / SIP - an IP GSM gateway will connect to a Voice Over IP Telephone system that allows the use of IP trunks. IP trunks are an alternative to traditional analogue or ISDN telephone lines and allow telephone calls to be made via the internet to an IP service provider who can break out the calls to the traditional telephone network. A phone system with IP trunk capability can utilise the IP GSM Gateway as an alternative to making calls via the internet. The IP GSM Gateway will sit on the network and calls from extensions to mobile phones will be routed via IP to the IP GSM Gateway and delivered directly to the mobile phone GSM network. The most common type of IP GSM gateway uses SIP protocol to GSM.