How to Increase Analog Extension Range Using Media Gateways

How to enhance and extend the range of analog extension distance.There are many times where the analog extensions to be connected at a distant place like in factories, cottages and similar kind of places where the buildings are scattered and the number of extensions required is also at minimum.

If the number of extensions required at each building is in large quantity, then multiple PBX's can be interconnected, installing the multiple pbx's are not commercially feasible and of-course administration also when the required extensions are minimum, need single point of maintenance and easy operation. The simplest way to extend the pbx intercom is by interfacing it with media gateways like FXO - FXS pair.

Schematic diagram at the beginning shows the implementation of FXO-FXS gateways. Choosing the FXO-FXS media gateway devices depends on the number of extensions to be extended and usually these gateways are available in multiples of 4 or 8 ports.

What do the terms FXS and FXO mean ?

FXO are the devices which accepts the analog extension as input from the pbx, each extension is carried on single pair of copper cable and fed in the media gateway.

FXS are the devices contrary to FXO which delivers the analog extension to the subscribers on a normal single pair of copper cable.

What is required in between FXO and FXS device to carry extensions from FXO to FXS.All media gateways have ethernet ports which can be connected to Local area network or Wide area network.

(1) If customer has existing LAN, then same infrastructure can be used to integrate both media gateways.

(2) If LAN does not exist, intercoms can be extended using point to point RF Wlan.

(3) Depending on the local telecom regulations the same can be extended through internet, IP VPN, MPLS networks.

Extensions / intercom's are connected to the FXO device and the same extension is taken out from the FXS device at the other end. This topology is best suited for PBX having less loop resistance and in need of long range intercoms there by minimizing the cost of raiser cable and maintenance.