An ISDN 2 Gateway will usually be installed in between the PBX and main ISDN 2 connection from BT. this is known as ‘Pass Through’ mode. The Gateway looks at all outgoing traffic from the PBX and sends any call destined for an 07 number out to GSM.

However, since you may have more than one ISDN2 connection on your PBX, this Gateway will not capture all of the calls going out on the other lines.

We can obviously fit gateways to these extra lines, but often we install ISDN 2 units in a dedicated port scenario instead. This leaves all of your existing lines free to make and receive landline calls, whilst the GSM gateway routes calls out to mobiles. This again may require an additional card and the involvement of you maintainer to perform the necessary programming. ISDN2 gateways share many of same functions as the ISDN30 units, though obviously on a much reduced scale.