The number of system telephones depends on the power consumption of the existing devices. The maximum power consumption at the internal S0 must not be exceeded.
Available power: max. 4 W per internal S0 bus (all telephone systems with internal S0 bus except COMpact 2204 USB and COMpact 3000)
Required power of the system phones:
Available power at the internal S0 bus of a COMpact 2204 USB: max. 2 W.
Power available on the internal S0 bus of a COMpact 3000 ISDN/analogue/VoIP: max. 2.5 W.
Depending on the constellation, various telephone combinations are possible on the COMpact 2204 USB or COMpact 3000 ISDN/analog/VoIP, e.g. (max. 2 system telephones):
COMfortel 2500 with key extension COMfortel Xtension30 or COMfortel 2600 with key extension COMfortel Xtension300 can only be operated with the power supply unit COMfortel XT-PS.