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