By default, the number of the caller is shown in the display of your Gigaset telephone. You do not have to make any other settings on your Gigaset telephone. However, if the caller's number is not displayed, this can be due to the following:

- You have not ordered CID from your network provider or
- Your telephone is connected through a PBX that does not transmit all information. Is your telephone connected through a PBX/gateway? 
You can establish this by checking for an additional device connected between your telephone and house connection, e.g., a PBX, gateway etc. 
In most cases, simply resetting this device will remedy the situation: 
- Briefly disconnect the power plug of your PBX. 
- Re-insert the plug and wait for the device to restart. 

If the caller number is still not displayed: 
Check the CID settings of your PBX and activate this function if necessary. In the user guide for the device, search for the term "CID" (or an alternative term such as "phone number transmission", "caller ID", ..). 

If necessary, contact the device manufacturer. If this does not resolve the problem, it is possible that your network provider does not support the CID service for this number. 

Have you ordered the CID service from your network provider? 
Check whether your provider supports Caller ID (CID) and that the function has been activated for you. If necessary, contact your provider.