In theory your dial plan is a required part of the NEC 2000 IPS system programming, whereas the LCR plan programming isn't. The LCR plan is accessed via the Dial Plan. Once you have built a Trunk Group you usually access them via an LCR plan - this enables you to bundle lots of trunk groups together in one big plan and decide on restrictions and specifics of how it's used - like what numbers should be restricted, how many numbers to wait for before sending the string the trunk itself. Taking a step back for a moment it's worth mentioning that in this subject arena, you have Trunks, Trunk Groups and LCR Plans.Ī trunk is usually single line (or channel) - but when you have hardware like ISDN2 or ISDN30 circuits, you have to bundle lots of trunks together in one big configuration, so when you need to use it, you select anything that is available on it! This forms a Trunk Group. This will most likely be a trunk, such as an analogue circuit, ISDN2 or ISDN30 circuit or a SIP trunk.
The most common use for this (in the UK, at least!) is using 9 to select the first preferred trunk to the PSTN. Sometimes it's necessary to add or change your numbering plan, so as to enable or disable users of the NEC 2000 IPS phone system to select a specific trunk when dialling a number.