This attribute holds the provisioning related to call collision
resolution. Its value must be that same as in the adjacent PBX, at
the other end of the PRI. To provision the call collision resolution in
Nortel's SL1 and Meridian 1 PBXs, the network operator responds
to the prompt SIDE by entering either MAS or SLAV. So if the
SLAV was entered, then the adjPbxSide has to be provisioned slave.