194 / General System featuresModular ICS 4.0 System Coordinator Guide P0881591 Issue 01Line poolsA line pool allows each telephone access to external lines froma group (or pool) of external lines. You can access such linesby pressing an intercom button and entering a line pool accesscode or by pressing a memory button programmed with theline pool feature code and a line pool access code.Overflow call routingIf a call comes in for a target line that is busy, Norstar routesthe call to the prime telephone for that target line. If there is noprime telephone assigned to the target line or if a call cannotbe directed to a target line, the call goes to the prime telephonefor the external line used.Overflow routing for incoming calls is used with the RoutingService programmed by your installer. A Service must beactive for overflow routing to be in effect. Overflow routing isnot available in normal service.M7100 telephoneBecause the M7100 telephone does not have line buttons, itsometimes works slightly differently from other Norstartelephones. Where other telephones can require that you selecta line button to answer a call, on the M7100 telephone yousimply pick up the receiver. Where other telephones requireTips -When you make a call and the programmed routeis busy, you hear the expensive route warning tone andsee a display indicating that an expensive route is beingused. To avoid using the normal, expensive route, releaseyour call.Because overflow routing directs calls using different linepools, a call may be affected by different line filters whenit is handled by overflow routing.
