Branch office dialing plan 27Branch office dialing planSince IP Phone users can be located at a branch office equipped with anSRG, the routing of calls to the local gateway is important (especially whentoll charges apply to calls made from the central Call Server that controlsthe telephone). The administrator can configure digit manipulation throughzone attributes for IP Phones to select a main office or branch office thatprovides PSTN access local to the destination of the call.Calls from the PSTN to users within the network can be routed with thevarious ESN numbering plan configurations.To access local PSTN resources, outgoing calls can be routed using ESNas well as zone parameters that enable digit insertion. The zone parametersforce calls made by an SRG user to be routed to the desired local PSTNfacilities.ATTENTIONOutgoing calls can include local and, optionally, long distance calls.Nortel recommends that the Branch User ID (BUID) be the same at thebranch office as the DN at the main office. A BUID has a maximum of 15digits. Under the recommended Coordinated Dialing Plan (CDP), the BUIDcan be an extension (for example, 4567). Under the Uniform Dialing Plan(UDP), the BUID is the user main office DN, the Location Code (LOC), plusthe Access Code (for example, 6 343-5555). The main office DN must bean ESN compliant DN. See "ESN Access Codes" (page 27).The SRG only supports only one dialing plan option at a time. CDP andUDP dialing plan options cannot be configured at the same time in thesame system.For more information about dialing plans and configuration, see "DialingPlan configuration" (page 43). For more information about the branchoffice dialing plan, see CS 1000 Main Office Configuration for SRG50(NN43001-307).ESN Access CodesESN data is configured with two Access Codes, called AC1 and AC2.AC1 normally applies to long distance calls, whether placed on or off thecustomer’s private network (for example, dialing 6). AC2 normally applies tolocal calls (for example, 9). For more information, see Electronic SwitchedNetwork Reference—Signaling and Transmission (NN43001-280).Nortel Communication Server 1000Main Office Configuration Guide for SRG 50NN43001-307 02.02 StandardRelease 5.0 3 December 2007Copyright © 2005-2007, Nortel Networks.