Siemens and DeTeWe W48 telephone
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.
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.
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)
- Remove the original line cord.
- Connect white of the new line cord to terminal b.
- Connect red of the new line cord to terminal a.
- On one tag of the capacitor locate the white wire - disconnect and
insulate this wire.
- 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.
- The other end of the resistor connects to the capacitor terminal, where
the green wire was removed.
- 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 right. The 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