MLU FORUM - Wireless of the Week

The communication hub of a Divisional or Brigade H.Q Signal Office was a 10 line UC10 Switchboard. Connecting the 10 pairs of wires between the H.Q. and its outstations quickly and correctly was enabled by specialized equipment. Outside, often hung on a tree or a pole, was a ‘Boxes, Terminal, Signal Office, Mk. II’ that allowed all the incoming wires to be wired to one single panel. Output from the Boxes, Terminal was condensed into two cables with 5 pairs of lines each terminating in two 5 pin plugs. These cables plugged into ‘Frames, D, and P., 10-Wire, Mk. 1*, Sets’ which not only organized and insulated the incoming lines but also protected them with fuses and lightning protectors.

Boxes, Terminal, Signal Office, Mk. II came in a metal reinforced teak box 17” tall by 5-1/2” wide by 3-3/4” deep weighing 34 lbs. There were 10 holes in the side to admit line wires and a rope handle which could be used to suspend the box from a support. The 10 wires were connected to slotted terminals on a teak panel located inside the box. The left terminals had a blue painted stripe to indicate ‘ground’ and the line terminals on the right were marked with a red stripe. Inside the box lid was a white ‘ivorine’ panel on which the identities of the line could be penciled on. Connected to the panel were two 30 yard cables, each containing 5 pairs of wires and ending in a 5 point plug; red for pairs 1 to 5 and black for pairs 6 to 10.

Frames, D, and P., 10-Wire, Mk. 1*, Sets came in a wooden carrying case 11-1/4” long, 7” tall, 12” deep and, complete, weighed 18 lbs 14 oz. The “D” and “P” stood for ‘Distribution’ indicating the unit was designed for routing incoming and outgoing cables and ‘Protection’ indicating the attached telephone and telegraph apparatus were protected from damage due to high voltage by way of removable fuses and carbon type lightning protectors. The die-cast frames themselves, once removed, were secured to the lid of the box with knurled screws; the 6-10 frame on the bottom with the 1-5 frame secured to the top of it. Incoming cables from the Boxes, Terminal, Signal Office, Mk. II were plugged into sockets on the left side of the frame and output cables connected from sockets on the right side to either the UC10 switchboard directly or a Superposing Unit (3 Transformer) which was itself connected to the UC10.

The two Frames, Sets shown in the manual are marked as made by Venesta Ltd. in 1939 and A. C. Cossor in 1936.

Has anyone come across a surviving example of either of these?