1986 – Nov – de Visser – MetRail – Integrated Services Digital Network (ISDN)

P. de Visser Rail Engineering Group, Signals & Communication Engineer The high operating costs, the unreliability and the lack of expansion capacity of the MetRail communication network has resulted in the replacement of the following telephone exchanges:- a. The Ericsson OS1029, a SO year old hybrid rotary and step by step exchange located in the old Head Office at 67 Spencer Street, which provided 1500 extensions; b. The Ericsson ARD571, an 11 year old cross bar-gxskange-located at the Electrical Control Centre in Batman Avenue, providing 270Bextensions; c. A modified Ericsson OS1029, an 18 year old hybrid step by step crossbar exchange located at the Spotswood Stores Depot, providing 500 extensions. As well as these, a number of smaller PABXs and intercom exchanges were also replaced.