ERICSSON
SWITCHBOARD No's 655 - 657
 

No. 657 shown pictured to the right.

Each line is provided with all indicator for calling, and a number of jacks (differing according to the size of the board) arranged in a vertical row under the indicator. As the calling indicators are in a horizontal row, there are under these a number of horizontal rows of as many jack holes as there are indicators. Each jack consists of two springs connected to the corresponding line, and two others placed symmetrically to them, which are respectively connected to the corresponding springs of all the other jacks in the same horizontal row.

Keys are provided on the shelf for putting the operator's hand micro-telephone into the circuit.

One key at the right-hand end of each horizontal row of jacks is for ringing, the corresponding ring-off indicator being at the other end of the row. A hand micro-telephone and hand generator for operating, and a night bell and night-bell switch complete the equipment.

A number of plugs are provided for making the connections, this being accomplished by simply putting a plug into one of the calling subscriber's jacks, and another one in the same horizontal row of jacks into the called subscriber's number.

Taken from the Ericsson Telephone Catalogue 1903

Last revised: October 11, 2019