TELEPHONE No's N1720 - N1731

N1725 N1725B

For use with N1470 type master station and used as side stations on loudspeaker telephone systems.

A warning lamp is fitted for each master station button.

Pressed steel case with Bakelite handset.

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Code No. No. intercom lines No. master lines Type
N1720 5 1 Table
N1721 5 2 Table
N1722 10 1 Table
N1723 10 2 Table
N1724 15 1 Table
N1725 15 2 Table
N1726 5 1 Wall
N1727 5 2 Wall
N1728 10 1 Wall
N1729 10 2 Wall
N1730 15 1 Wall
N1731 15 2 Wall

Introduced around 1933.

C. B. Intercommunication Telephones

When the side stations are simple call and reply to the master, N1594 is the instrument used.  It is a black moulded Bakelite table set of modern design, fitted with a push button for calling.

Side station instruments N1721B - N1731B with intercommunication facilities are similar to the popular standard intercommunication telephones, type N1620A, with the addition of two pre' keys and lamps associated with the master station lines.

The highly efficient Bakelite micro-telephone is standard for both types of side station instruments.
The operation of this loudspeaker system is similar to that of the ordinary intercom, system and is as follows:
A call to the master station is indicated there by a lamp and is answered by operating the key associated with the calling lamp.

A call by the master to a simple side station N 1594 is indicated by buzzer and answered by removing the micro-telephone.

A call by the master to an intercom, type of side station is indicated there by a lamp which will glow even if the side station is engaged. The call is answered by removing the micro-telephone and pressing the button associated with the calling lamp.

Conference can be established by the master station operating the keys of the desired side stations.

Taken From the Ericsson catalogue No. 49

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Last revised: February 28, 2021