Type CK 550
Intermediate Wall Telephone for 2 Metallic Circuits
Common Battery System
FRAMEWORK, polished walnut.
MICRO-TELEPHONE. PE105l, with cord RS6500 (0ld No.2061), resting on a cradle-switch.
GENERATOR. RH 2400, 2-magnet.
RINGERS. Two ringers, each of 1,000 ohms resistance, are fitted.
INDICATOR of the star type is fitted, for the purpose of showing when a substation telephone is speaking with the Exchange. (A condenser of 1 microfarad capacity is connected in parallel with this indicator.)
LINE CONDENSER, with a capacity of two microfarads.
This telephone is provided with a 3-way switch, enclosed line terminals, and a clip for papers.
The intermediate station is in communication with the Exchange or with the sub-station, depending upon the switch being in a right or left-hand position.
If the switch is in its central position, the Exchange and the substation telephone are in speaking connection with each other.
Signals from the Exchange or sub-station telephone are heard at the intermediate telephone irrespective of the position of the switch. If the intermediate telephone is speaking on either line the conversation cannot be overheard by the other line.
Height 22.50 inches.
Weight, 13.25 lbs.
Taken from the Ericsson Telephone Catalogue 1912
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