The dutch telephone company KPN provides ISDN equipment based on the Ackermann Euracom series. The latest version is the ISDN HomeVox (based on the 260F), where it is possible to connect a TFE. The predecessor of the equipment is called the "ISDN 2-8+ centrale". This equipment is based upon the Ackermann Euracom 181. Although with the KPN version it isn't possible to connect the door-bell (or the complete TFE functionality) to the ISDN equipment. This is because KPN had some reasons to strip the standard TFE hardware. But it is possible to add the "stripped" hardware because the wholes in the Printed Circuit Board (PCB) still exists.

How does the hardware look like?

Figure 1 (left picture) shows the "not connected" wholes when the "TFE-hardware" doesn't exist. Figure 2 (right picture) shows how the original equipment looks like including TFE functionality (other types of relays used).

Dutch version of the PC-Board
Fig. 1: Dutch PC-Board without TFE support.
Dutch modified PC-Board
Fig. 2: PC-Board with TFE support.
(Please click on the pictures to view a more enlarged foto.)

What do you need to modify the hardware?

  • Soldering-bolt and/or a solder piston
  • Two relay Siemens V23042 or similar
  • One Symmetrical Transient Voltage Suppressor TISP2180
  • Eight solder pins and a connector to connect the external wires
  • Equipment to protect against electrostatic damage
  • Courage to work on your ISDN equipment
  • The knowledge that the guaranty form KPN is over after this modification

What do you do? or step-by-step procedure:

  1. Make sure the equipment isn't connected to the main voltage
  2. Open the cover (see manual)
  3. Remove the PCB from the plastic cover
  4. Remove the solder from the PCB wholes
  5. Add the two relays and the TISP2180 as shown in figure 2
  6. Add the eight solder pins, so it is possible to connect the TFE wires
  7. Put back the PCB into the cover
  8. Switch the TFE enable jumpers to the right position (see Fig 2)
  9. Close the cover
  10. Connect the equipment to the main voltage
  11. Configure the equipment using the manual or see ../ec-md1.htm for more information's (in german)