Distribution point box (DP) is used in terminating cables of secondary telephone networks to the cable pairs of subscriber lines. 

The STB module also called VX connection module provides a connection point between an exchange-side cable pair and a distribution pair. It incorporates a 5-point plug in module to provide continuity and a range of other options. 

It is equipped with GDT (Gas Discharge Tube) arrester in side the plug-in module, which forms the protection circuit for the protection of exchange room equipments and personnel against over voltage and over current, for mainly as follows:

The surge voltage caused by lightning on or around the outside lines.

The short-time AC voltage inducted on external lines, when the power line, the power system or the electric railway system is broken down in the neighborhood of the outside line.

The outside line directly collides against a 220 V power line.

It is especially recommended for outdoor connections where the environmental conditions are extremely aggressive.

The connection modules are designed for mounting on a standard DIN rail and can therefore be mounted in a variety of housings in whatever quantities are required. The small footprint (2 cm wide) ensures a compact product.