yes, normaly ars/lcr uses lead numbers not lenght of number, so you will depend second inter-digit timer or # to say I am finished dialing.

the panasonic could use other system codes and tie table for calling extensions on the nortel system with lead number and number of digits

but only with co connections to the nortel, if using pri as extension on tde, you will have to give it 1 digit extension and have the nortel answer it with dial tone

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