
5.1.3 PBX Requirements for Inband Integration
Minimum Loop Current | 20 mA |
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Minimum Line Voltage | 7 V DC |
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Minimum Ringing Voltage | 40 V AC |
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DTMF Signaling
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 signaling.
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 dialed.
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 dialing 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 dialing 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.
3.Checks to see if the called subscriber is in, out, or on another line, and whether or not that subscriber accepts the transfer.
4.Completes the transfer (by going
If the PBX does not provide screened transfer from an SLT, the VPS cannot give callers the option to leave a message in a subscriber’s mailbox.
TEST: Place a trunk (CO line) call from an SLT. See if you can set up a screened transfer to another extension. Next, try the same test with an intercom call. (The VPS may have to transfer both types of calls.)
Document Version 3.0 2010/06 | Installation Manual |
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