TELEPHONE No. 51
Telephone, House, Wall, intercommunication, 15 way, non-secret.

The handset is a Telephone No. 30.

Found in the 1915 and 1928 GPO Rate Books and made obsolete in 1947.

Circuit Diagram - TL 230.

Circuit Diagram - N151.

Information on all House telephone systems

 
 
BACK Home page BT/GPO Telephones Search the Site Glossary of Telecom Terminology Quick Find All Telephone Systems

Last revised: November 03, 2025

FM