3.1 GUIDELINES FOR INTEGRATIONInstallation Manual 513.1.4 PBX Requirements for IntegrationThe PBX must have certain capabilities and features to work with the VPS. (Although thissection includes tests to help you evaluate the PBX, it may be necessary to refer to the PBX’sdocumentation for detailed capability and feature descriptions.)Single Line (Tip/Ring) Port CircuitsThe VPS can only be connected to a PBX that supports SLTs. Some PBXs need an OPX cardto provide this connection. However, some OPX cards do not provide all the capabilitieslisted in this section.Following are the minimum current and voltages that the PBX must supply:Extension to extension Touchtone SignallingFor system users to access VPS services and features, they must be able to send touchtonesfrom their telephones to the VPS port. As a general rule, SLTs can perform extension-to-extension touchtone signalling; however, many proprietary telephones cannot. Some PBXsneed to be programmed to make proprietary telephones use touchtone signalling.If the PBX does not provide extension-to-extension touchtone signalling, VPS servicesand features will be limited.Message Waiting Notification from an SLTThe PBX extensions should light a lamp or receive broken dial tone when the Message-Waiting-Lamp-On code is dialled by the VPS. The VPS functions best when the extensionnumber of the voice mailbox owner follows the Light-On or Light-Off code. On some PBXs,however, the extension number is dialled first, followed by a flash (recall) and then the Oncode. This presents a problem if the extension is answered before the VPS sends the flash(recall) signal.If the PBX does not provide message waiting notification from an SLT, the VPS can onlynotify mailbox owners by dialling a beeper (pager) or user-assigned extension number.This process slows down VPS performance as it dials the beeper (pager) or extension numberand waits to confirm notification. The beeper (pager) or user-assigned extension notification ismeant to be used for necessity, usually for mailbox owners who are often out of the office (e.g.,Table 3-2Minimum Loop Current 20 mAMinimum Line Voltage 7 V DCMinimum Ringing Voltage 40 V ACTEST:Call an SLT extension from the telephone in question. When the callis answered, see if the person receiving the call hears touchtones whennumbers are dialled.
