5100 BCS

When the restriction preventing the RTT from installing telephone systems with more than five external lines was lifted, the 5100 BCS was introduced. This was one of the largest exchanges the RTT had at the time. It offered a capacity of 8 external lines and 40 internal lines and could be expanded to 20 external lines and 92 internal lines via a “DAISY BUS” and an additional cabinet. The exchange could be programmed via the operator’s handset. The system could connect both standard pulse/tone telephones and two operator’s handsets, and offered functions that are still familiar today (speed dialling, music on hold, etc.). A printer could also be connected to it to print out the configuration parameters or call records, for billing or auditing purposes.