All Trunks Busy (Atb)
 

* 1.An equipment condition in which all trunks (paths) in a given trunk group are busy. Note: All-trunks-busy registers do not indicate subsequent attempts to reach trunk groups
English Related Words* above all
* according to all accounts
* after all
* against all odds
* against all risks
* all
* all a case
* all a long
* all aboard
* all aboard!
* all abroad
* all afire
* all agog
* all agree
* all alone