ETL (Ericsson Telephone Ltd) – Model N1636C10 Intercom Telephone

From the late David Charles Collection

Manufactured by Ericsson Telephone Ltd (ETL), a British subsidiary of Ericsson, this telephone is part of a series of internal intercom systems designed for business and institutional use.
This example, finished in ivory, is the model N1636C10.

Overview
The N1636 series was produced as a self-contained intercom solution, allowing communication between multiple internal extensions without connection to an external telephone network.
Key Details
• Type: Internal intercom telephone
• Capacity: Available in 5, 10, or 15-line configurations
• Colours: Black and ivory
o Only black units were supplied to the General Post Office (GPO)
• Power: 6-volt battery operation
• Wiring: Multicore cable system
As the number of lines increased, so did the complexity of the wiring. Once cable sizes approached roughly 40 conductors, the physical bulk and cost became prohibitive, effectively limiting further expansion of the system.
Model Identification
• N1636 – Base model
• C – Revision
• 10 – Colour code (ivory)
Usage Note
These sets were designed strictly for internal communication and cannot be connected to standard exchange lines.

As received.