Internet phone number

@wlduck , the device is a simple, functional device that connects to the TM network. It lacks features like you ask about. You can see your number using your T-Life app to manage your device and see your phone number. You can also use the T-Mobile internet app, but they are moving away from it. 

@wlduck "Why doesn't my T-Mobile Gateway 5G internet modem display my internet phone number?​​​​

I have the Arcadyan KV21 TM 5G gateway.  If I cycle through the gateway's display, my internet phone number is shown there.