No's PTD 50 & PTD 51


Loudspeaking telephones for use on Private Automatic Telephone Systems. Can be supplied with or without Direct Access Facility. A handset is provided to automatically cut off the Loudspeaker when private telephone conversation is desired.

P.T.D. 50
Loudspeaking telephone in attractive polished wood cabinet incorporating microphone, loudspeaker, standard B.P.O. pattern dial and three-position volume control switch. This telephone has an in-built amplifier and does not provide for working with other loudspeaking telephones. Can be supplied with or without direct access facility. The illustration shows a telephone fitted with this facility.

Height: 11.5in (292mm)
Width: 18in (457mm)
Depth: 9.25in (235mm)
Weight: 281bs (12.7kgs)

P.T.D. 51
This telephone has a separate amplifier incorporating the latest electronic switching feature enabling two loudspeaking telephones to converse with each other without the use of a “Speak - Listen” Key. Volume is adjustable by a three-position switch.

Code Height Width Depth Weight
ins mm ins mm ins mm lbs Kgs
Amplifier 8 203 15 381 7.6 194 18.75 8.4
P.T.D.51 11.5 292 18 457 9.25 235 21.25 9.5

From SIEMENS BROTHERS & CO. LIMITED catalogue No.500/54

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Last revised: February 27, 2022