Siemens and DeTeWe W48 telephone

A standard West German Post Office (Bundespost) design, this updated version of the W38 was imported in the 1950's and 1960's by firms who offered German PAX systems (such as Modern Telephones and Hadley Telecom).  The case and handset are made of Bakelite.  This design was made for the Bundespost by several West German manufacturers but only the Siemens and DeTeWe products were used in Britain.

Black, ivory.

PAX systems only in the UK, but also PABX's and the public network in Germany and elsewhere.

There was a corresponding wall telephone. DeTeWe versions have the name Modernphone screen-printed on the number card holder. Siemens versions can have on the back a circular red transfer with the name of the installer (Hadley of  Birmingham).

Picture courtesy of Paul Follet.

Click here for the Circuit Diagram

Click here for the Siemens and Halske circuit wiring diagram (with colours)

Click here for the Hagenuk Kiel schematic circuit diagram

Click here for the Krone circuit and wiring diagram (with recall switch)

For more information click here

How to wire a W48 to work on the UK plug and Socket system (also works for the W49 model)

  1. Remove the original line cord.
  2. Connect white of the new line cord to terminal b.
  3. Connect red of the new line cord to terminal a.
  4. On one tag of the capacitor locate the white wire - disconnect and insulate this wire.
  5. Locate on the other tag of the capacitor a green wire - disconnect just this wire and connect to one end of a 3.3k resistor.
  6. The other end of the resistor connects to the capacitor terminal, where the green wire was removed.
  7. Connect the blue of the new line cord to the same tag of the capacitor where the new resistor is connected.  This tag is becoming a little crowded so it may be better to connect a piece of wire to the tag and then connect the other end to the blue of the line cord and the resistor.

These phones are not approved and should not be connected to any public network

For more information on Siemens telephones go to

W48 Internals (Krone version)

The capacitor is the grey square box to the left and the induction coil is the amber coloured
object to the rightThe switch hooks are central.  Note that there is a resistor soldered
on the capacitor tag that is nearest the edge of the base.

The capacitor and resistor are clearly marked in the picture above

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Last revised: November 27, 2022