M973.242.9d

Alarm

Object ID
M973.242.9 a-g
Category
Tools and Equipment for Science and Technology, Regulative & Protective T&E
Date Made
circa 1920
Materials
metal; glass; wire; wood
Place Made
London, England
Description
Marconi Auto Alarm system, signals 12 four second dashes (international distress code). Any four received will trigger alarm bells.
a) Selector/rejecter: Type 33, P.S.#2106-A, inst.#13161. 27cm. by 26cm. by 20cm. metal case with glass front. Nine screw terminals on top and rear. "No 1 Bell/ No 2 & 3 Bells/ + 24v-1 1 input 2/ 1 N.V. RELAY 2". Recessed Dash Relay adjust (F-s), signal relay, and space relay adjust. Covered bridge bell and test keys.
b) & c) Keys for recessed adjust nuts. Square, female tip. "Made in England" at top on one side, "12" on other. 7cm. by 4cm.
d) A Marconi Auto Alarm Receiver in a wood case with a metal front plate. At the top of the wood case there is a small brass plate which reads "Marconi Auto Alarm Receiver Type 332 PS No 2684 A Inst No 13355 Marconi Wireless Telegraph Co. Ltd. London." At the top of the front metal plate there are filament and Relay Current adjust screws with calibrating filament and relay current numbers above each screw. In between there is a small white synthetic square which reads "Best Adjustments VARIO A.T.I. Reaction." Below this are three silvered Marconi Wireless vacuum tubes, the tube on the right has a black wire that runs from the base of the tube to the first of five screw type telephone hookups. From bottom to top these hookups read "1st MAG", "2nd MAG" and "G." Below the hookups it reads "Telephones." Below the vacuum tubes there is a glass faced galvanometer (EN 1111880), scaled from 0-30 in unit increments. There are three more adjusting screws below the galvanometer; the left one reads "variometer" the middle reads "A.T.I." and the last reads "Reaction". There are nine screw terminals at below the adjusting crews, from left to right they read "A E + 24V - H.T. + L OUTPUT 2 IN.U.RELAY 2".
e) & g) Bells. One each for bridge, wireless office, and R.O. cabin. 21.5cm. by 12.5cm. by 8.5cm. wooden base with dome-type bells and simple clapper extending from housing on top. Type 177M.
Related person/organization
created by: Marconi's Wireless Telegraph Co. Ltd.