(thing) by tripitaka Thu Aug 09 2001 at 14:39:31
In telecomms, the B number is the called party, or current call destination.

If Mike on 212-1234 calls Dave on 212-5678, 212-5678 is the B number and 212-1234 is the A number

This value can change during a call if number translation is being used.

I like it!