yes, it is telling the system that anything starting with 6 will go out on pri/t1 or reading back , you would add 2 and 5 as other system and in tie table tell it what trunk to go out on.

so dialing from tde would be a 3 digit operation

Make sure the trunk group that is linking the system to have cos 1 and co - co duration timer is set to none

“I have not failed. I've just found 10,000 ways that won't work.”