Unknown Buzzer GPO/Military
 

Had a large quantity of 1920s radio parts brought in last week. Amongst these was a buzzer built around an iron block mounted on a mahogany base. In paint on the top is marked P18 238 No148, on the front is stamped R C T below each terminal. Works quite efficiently with 6 volts across R and T. Any ideas as to the origin of this device.
Neil

Re: Unknown Buzzer GPO/Military
 

I have found a picture of the same type of buzzer in a 1920's Electradix catalogue "High class,heavy made buzzer. Massive Platinum Contacts, Fitted Three Terminals. 5/-". Doesn't say anything about origins. On the illustration the markings are "DV17 2?75".
Mike.

Re: Unknown Buzzer GPO/Military
 

Thanks for that information Mike, that is most helpful, it has given me a definite lead. I quite thought that it was later than 1920s looking more like a WWII component but the mahogany base does date it somewhat.
Neil

Re: Unknown Buzzer GPO/Military
 

Looks to be a GPO item - the lettering on top decodes as -

P = manufacturers codes for firm 'P W Paul' manufactured in 1918. It is the fifth version of the item. The GPO used '234' for first version, 235 for second, 236 for third and so on. Likelyto be a 'Buzzer 148' or the like.

Can't find my volumes of GPO drawings of small items from 1899 & 1909. Trawling through over 100+ volumes of N & TG diagrams from 1917 onwards would take a long time. BT Archives when they reopen may be able to help as it will listed in the Vocabulary of Engineering Stores of the era.