scope:

This instruction applies to those Network Rail switches which are not leased to a third party and are primarily installed to support Network Rail's business requirement in offices and ICCs.

Electronic PABX Switches which are configured as concentrators and installed to handle safety critical communications, such as those in Signal boxes and Electrical Control Rooms are to be maintained as detailed in NR/L2/TEL/30085 Maintenance of Electronic PABX Concentrators.

The switch installation may, by design, be constructed from a number of remote nodes or shelves. These shall be considered as separate switches and subject to the applicable procedures in the relevant appendix.

The maintenance requirements for the Power Plant and Batteries used to support Electronic PABX switches is detailed in NR/L2/TEL/30081.

The maintenance requirements for Voice Recorders is detailed in NR/L2/TEL/30082.

The testing of emergency facilities (999 - 112 short code dialling) is detailed in NR/WI/TEL/30123, Communications with Emergency Services - ETD Network Testing Procedure.

Purpose

This instruction defines the maintenance requirements for Electronic PABX switches owned by Network Rail.

The purpose of maintaining PABX switches is to decrease the incidence of failures through deterioration and to identify potential failures before they become service affecting.