The long thin ‘dot’ contact spring is on the inside of the rubber bit, so that the rubber pulls the spring away from the dot contact. This gives the adjustment for ‘thick’ and ‘thin’ dots. The pendulum (reed) consists of an arm along which the weight can be moved. The position of the weight determines the speed at which the pendulum oscillates and therefore the speed of sending. Please note that (on many Simplex Auto bugs) the bar, carrying the bakelite finger and thumb piece, is joined to the remainder of the arm. It is only joined, so that a comfortable working height can be chosen.

To quote a former Australian Postmaster “I have never seen it in the full upright position. In fact, most telegraphers used it straight, although I like mine slightly raised”. The Simplex Auto key is a semi-automatic mechanical morse code transmitting key, invented about 1920 and produced with the same basic design until the 1950s. They were professionally used until the 1970s.

The original manufacturer was LEOPOLD GILBERT COHEN, a Telegrapher in the Melbourne Chief Telegraph Office (CTO). In 1923 the Simplex Auto was adopted by the PMG as a standard sending aid for the Commonwealth of Australia and was also used in Railway Telegraphic Services. Simplex Auto keys that belonged to the PMG and were issued to PMG operators, have P.M.G. (or PMG) followed by a 3-digit number stamped on their bridge.

Cohen stopped making Simplex Auto jiggers after he went into the Army on 13 November 1939. His name appears on the “The Simplex Auto” labels up to about serial 5xxx. There is only one recorded Simplex Auto with an early 1xxx number and none in the 2xxx range. Therefore, Cohen must have made around 3000 Simplex Auto keys. When in 1939 Cohen’s name disappeared from the label, the name STUART PERRIN appeared for a while. It is believed that Perrin was Cohen’s brother-in-law. After that the label is without a surname and simply says ‘Melbourne Victoria’ Nine (9) models of Simplex Auto keys were made. For more details see MM88 of February 2004. The highest recorded Simplex Auto key number is 7335.

The Auto Simplex keys without nameplates were made for the military and other departments, such as Civil Aviation, PMG etc. long after Cohen stopped making Simplex Auto keys. Ron McMullen has one that is engraved C of A 45 on the bridge and was issued by PMG to a Postal Clerk in 1957.

Extracts from the great article "Australian Gems. The Pendograph and the Automorse" by Ron McMullen in Morsum Magnificat 88/Feb.2004, page 14 on.

"BK"