FRITZ!Box 7590 Service - Knowledge Base
FRITZ!Box does not transmit incoming caller ID when calls are diverted
The FRITZ!Box does not transmit incoming caller ID when calls are diverted. Instead, it transmits the number of the line that the FRITZ!Box is connected to.
Telephony provider does not allow transmission of caller ID
The telephony providers are responsible for transmitting caller ID. With call diversion, providers only allow the FRITZ!Box to transmit the telephone number of the line that it is connected to.
If your telephony provider supports the setup of call diversion and you set up call diversion directly with the provider, the caller's number is transmitted.