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5.1 Guidelines for Inband Integration
Following are the minimum current and voltages that the PBX must supply:
Minimum Loop Current | 20 mA |
Minimum Line Voltage | 7 V DC |
Minimum Ringing Voltage | 40 V AC |
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DTMF Signalling
For system users to access VPS services and features, they must be able to send DTMF signals from their telephones to the VPS port. As a general rule, most SLTs can send DTMF signals; however, many proprietary telephones cannot. Some PBXs need to be programmed to make proprietary telephones use DTMF signalling.
TEST: Call an SLT extension from the telephone in question. When the call is answered, see if the person receiving the call hears DTMF tones when numbers are dialled.
Message Waiting Notification on an SLT
When the
If the PBX does not provide Message Waiting Notification on an SLT, the VPS can only notify mailbox owners by dialling a beeper number or
This process slows down VPS performance as it dials the beeper or extension number and waits to confirm notification. The beeper or
TEST: See if dialling the On code from an SLT can turn on an extension's message waiting indicator.
Screened Transfer from an SLT
The PBX must provide a screened transfer from an SLT for the VPS to function properly.
A screened transfer:
1.Puts the caller on hold, usually with a hookswitch flash.
2.Dials the extension.