If you want to assign an ISDN number so that all the Internet calls use this specific number, you can try as follows:

Open the "ISDN Settings" page of the Billion ISDN product from "Control Panel\System\Device Manager\Network Adapters\Billion ..." Input the "Calling Party Number" of "ISDN channel 0" and "ISDN channel 1" with the ISDN number that you want to use for internet access.

This setting will take effect after you restart the PC.

This setting is valid only when you configure our NDIS WAN miniport driver ("Billion ISDN channel 0" or "Billion ISDN channel 1") as the modem device in Dial-Up Networking (DUN). You should not configure DUN to use "RVS ISDN PPP" as modem device.