FRITZ!Box 7490 Service - Knowledge Base
Pin assignment of cables, adapters and ports
Your FRITZ!Box came with various cables and adapters to connect it to the DSL line and connect your telephony devices to the FRITZ!Box.
Note:The FRITZ!Box is available in several different product variants, each of which is delivered with different components. For the exact contents of the package, see the information printed on the FRITZ!Box packaging.
1 DSL/telephone cable (Y cable)
The cable wires for DSL lead from the middle pins 4 and 5 of the plug on the single cable end to the middle pins 4 and 5 of the (gray) DSL plug at the split end of the cable (see fig.).
Note:If you hold an RJ45 plug so that the cable is hanging down and the golden pins are showing upwards and towards you, pin 1 is on the right-hand side, and pin 8 on the left-hand side.
The cable wires for landline telephony (ISDN/analog) lead from pins 1, 2, 3, 6, 7 and 8 of the plug on the single cable end to pins 4, 5, 1, 8, 3 and 6 of the black telephone plug at the split end of the cable (see fig.).
Fig.: Pin assignment of the DSL/telephone cable
2 "FON S0" port on the FRITZ!Box
The cables of ISDN devices connected to the "FON S0" port on the FRITZ!Box must be assigned as follows:
Fig.: Pin assignment of the ISDN cable
Note:You can have a technician install an S0 interface connected to the "FON S0" port. The "FON S0" port is terminated (two 100 Ohm resistors are switched on the "FON S0" port in the FRITZ!Box).
3 RJ11 sockets of extensions "FON 1" and "FON 2"
The RJ11 sockets "FON 1" and "FON 2" only use the two middle pins.