MERLIN LEGENDCommunications System Release 6.1 | Issue 1 |
System Planning 555-661-112 | August 1998 |
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2Control Unit Configuration
Numbering the System | Page 2-20 |
To calculate the total number of TTRs that are required by the system, do the following:
1.If the system has a VMS, use Table 2–3 to find the number of TTRs required by the system to support the VMS.
2.Estimate the hourly call volume for all calls originating from single-line telephones, incoming calls (including private network tandem tie trunks) on Remote Access and DID lines, all calls on tie lines, and calls routed to the VMS. Use Table 2–4 to find the system requirements for TTRs based on the estimated hourly call volume, and whether Account Codes are used.
NOTE:
You must consider the call traffic across a private network when estimating the number of required TTRs. This includes calls on analog tandem tie trunks and T1-emulated tandem tie trunks. In addition, if your private network includes Centralized Voice Messaging, you must consider the call traffic coming across the private network for the voice messaging system and the TTRs required for the updating of Message Waiting lights (Release 6.1 or later systems). For this updating, a TTR is required at the sending end and the receiving end. If the systems in the private network are connected by PRI trunks, no additional TTRs are needed.
3.Add the number of TTRs obtained in Step 1 and Step 2. If the Group Calling Prompt-Based Overflow setting (Release 6.0 and later systems) is not being used, go to Step 6.
4.If the Group Calling Prompt-Based Overflow feature is being used, add the number of TTRs needed for the primary delay announcement devices that are assigned to those calling groups. Use Table 2–5 to determine the TTR requirements for the primary delay announcement devices.
5.If applicable, add the number of TTRs needed for the secondary delay announcement devices that are assigned to calling groups using the Prompt-Based Overflow feature. Use Table 2–6 to determine the TTR requirements for the secondary delay announcement devices.
NOTE:
If no announcement is used on a primary or secondary delay announcement device, no TTRs are needed.
6.Use Table 2–2 for information on the number of TTRs provided by each type of module, and to determine the number of TTRs already supplied.
7.Compare the total TTRs needed to the total TTRs already supplied to determine if additional TTRs are required.
8.Add a new module if more TTRs are required.
