Abstract: A network node 102 capable of detecting how many parties have collided during attempts to transmit on a bus 108. If more than one party has been detected to collide, the node 102 selects a backoff window from a larger randomized group of possible backoff windows than if the node had collided with only one other party. In this way, delays due to multiple parties colliding are minimized.

Abstract: A method for operating an ISDN PBX?110! for connecting M BRI lines?13-15! connected to a central office?12! to N terminals?21-28, 31-38, 41-48! connected to the PBX?110! (N>M), such that any B channel of any of the BRI lines?13-15! can be connected to any terminal utilizing a connect in accordance with Bellcore National Standard NI-2. Each of the terminals?21-28, 31-38, 41-48! is associated with one, and only one, of the BRI lines?13-15!. The present invention achieves its advantages over the prior art by defining a plurality of EKTS groups?1-4!. Each of the EKTS groups?1-4! includes at least one of the terminals?21-28, 31-38, 41-48! associated with each of the BRI lines?13-15!. When an incoming call is received for a terminal associated with a BRI line that is currently busy, the call is connected by emulating a connection to a second terminal that is assigned to free BRI line and which is also assigned to the EKTS group to which the first terminal is assigned.