My goal is to remove country code code from phone number, I live in Italy and my country code is +39, I have a Gigaset COMFORT A IP FLEX cordless phone connected to the Archer VR2800v router on my landline, so only via RJ11 telephone cable, no VoIP.

For every incoming call (from a cell phone to a cordless landline), the caller's number is prefixed with "00" and "39", as a result the number displayed on the cordless phone's display will be "00393456789231," not "3456789231" as I would like. This problem does not occur for outgoing calls (from a cordless landline to a cell phone).

I first contacted Gigaset technical support, and they responded as follows:

"The handset displays the information transmitted by the provider/router as CLIP/CNIP. Our device does not have any settings for this; this setting can only be made via the modem or provider."

below you can see the two photos that show how a telephone number appears on the cordless phone display.

INCOMING CALL: (The problem is present)

OUTGOING CALL: (The problem is not present)