RELAYS - LETTERED

Before the GPO started to number relays, they were either described or lettered. 

This page shows some of the lettered variety.  These were mounted on a wooden base which also had the terminals fitted.  Later a square base was introduced which could be fitted with spring clips and then plugged into a mounting.

The relays were enclosed in a tin cover with a glass, opening, window on the top.  This allowed visual inspection of the contact points when adjust via the Vernier screw on the side of the casing.

Relay, Standard A

For general telegraph purposes, except Wheatstone circuits.


 
 
Relay, Standard B

7 terminal rectangular base, with earlier supplies having only 6 terminals.


For Baudot sets and repeaters boards on which spring contact clips are used.

 
 
Relay, Standard BN

For Panels, Telegraph, For jacking-in to Baseboards, No. 26.


 

 
 
Relay, Standard C


 

 
 
Relay, Standard G


 

10 terminal rectangular base.

Used with Wheatstone receivers.

Diagram - TG261.
 

 
 
Relay, Standard GN

For Panels, Telegraph, For jacking-in to Baseboards, No. 26.


 

 

  
Relay, Standard H

12 terminal change-over relay with multiple windings on each bobbin.

Diagram - TG416
 

 

  
Relay, Standard HN

For Panels, Telegraph, For jacking-in to Baseboards, No. 26.

Base fits a Jack No. 48.
 

 
 
Relay, P1 B

 

 


 

Pictures

Relay ready to be inserted into mounting

 

Relay inserted into mounting

 

 
 
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Last revised: January 28, 2025

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