DBH 4003 and DBH 4103
The telephone combination DBH4003 and DBH4103 are suitable, when the distance between the devices is relatively large, e.g. for business owners who wish to have a telephone both in the shop as in the home. The intermediate device, DBH 4003, could be conveniently placed in the shop and the end device, DBH 4103, in the residence.

The intermediate device, DBH 4003 (pictured upper right), which has a black cover Bakelite, contains, besides the usual parts of a automatic device, a keypad with three buttons, one red for connection of line L1 , a white for line L2 and a black one for resetting both red and white buttons as well as an indicator to mark when wire L1 is occupied by the end device. For the internal call is the device equipped with a generator. The device is also equipped with two signalling devices, one is a polarized AC ringer which is mounted in a wall case.

The DBH 4103 (pictured lower right) is broadly similar to the intermediate telephone but has no indicator or keys.

By means of a DYY 1012 shelf, these devices can mounted on the wall.

Line L1, which is connected to the public exchange, is connected to the intermediate device. For connection between the devices require a two-wire line L2, which is connected through to wire L1, then the red and the the white buttons are restored on the intermediate device. In a from line L1, the microphones are fed from the telephone exchange. In the case of internal calls the supply current to the microphones a local battery, composed of three dry cells BKA 1002 or BKA 2002 giving a total of 4.5 Volts.  Suitable battery box BKY1002.

A facility containing these devices has the following function:
In the case of an external call from the intermediate device, the query is made to the end device during that line L1 is held; an external call can be transferred between the device to the end device; normally an external call from the one device cannot intercepted in the other, but through a switch in the intermediate device, you can intercept from this device for an external call from the end device, buttons are pressed except for the black button, the microphone is switched on, whereby calls can also be made from this device; an internal call can be made without line L1 being interrupted; if both the red and the green button in the middle of the devices are reset, the end device is through connected to the line L1.

If incoming calls are to be received on the intermediate device (e.g. when used as the main telephone) the red button must be pressed, whereby only the intermediate bell rings.

Incoming
Incoming calls are dispatched in the following way. The phone is picked up and the call is answered. On a request to speak to the end device the call must be transferred.  The white button is pressed, after which the generator is operated.  Line L1 is now on hold via a resistance. Once the desired information is obtained, the intermediate device can is connected back to the call on line L1 by the red button, which was constantly in the down-pressed mode, is pressed at the bottom, whereby the white button is triggered. If the call should instead be transferred to the end device, the black button on the intermediate the device, triggering the red and white buttonand the call is switched to the end device.

If, however, incoming calls are to be received on the end device, both buttons on the intermediate device rate be reset, whereby the ringers of both devices operate.

In the case of an internal call from the intermediate device, the white button is pressed, after which signal is given with the generator and the handset lifted off.  An internal call from the end device involves the generator and then lifting the handset.

Dimensions:
Height 139mm, width 233mm, depth 178mm.

Taken from the L. M. Ericsson Catalogue No. 610 (1939) - Swedish Translation

Last revised: June 07, 2024