5.1.1 What is Inband Integration?
In order for the VPS to function, it must be integrated with the PBX it serves. The type of integration that is used determines how voice (caller messages, VPS prompts, etc.) and data (extension status, button presses, etc.) are sent between the VPS and the PBX.
When the VPS and PBX use Inband Integration, voices are sent using analog technology, and data is sent using analog DTMF tones.
The PBX informs the VPS of the status of extensions by sending DTMF tones and Call Progress tones to the VPS. Similar to an extension user, the VPS places calls by going off-hook and dialing numbers. It starts call transfers with a hookswitch flash to put callers on hold and then dials the extension number, just like an extension user.
Signals Sent Between the PBX and VPS
PBX to VPS VPS to PBX
5.1.2 When to Use Inband Integration
The type of PBX and/or the type of extension cards installed in the PBX will determine whether Inband Integration should be used. Generally, if the VPS is connected to an APT/DPT Integration compatible Panasonic PBX, APT/DPT Integration—not Inband Integration—is the ideal integration method. See 1.1.7 Compatible PBXs for more information.
Note
• Certain VPS features are not available when using Inband Integration.
• Availability of VPS features depend on the PBX being used.
5.1.3 PBX Requirements for Inband Integration
The type of VPS, PBX, and PBX extension cards used will determine the availability of certain features. In order to use the features described in this section, you may need to test the PBX for compatibility or refer to the documentation included with the PBX.
Single Line (Tip/Ring) Port Circuits
5.1.3 PBX Requirements for Inband Integration
Minimum Loop Current 20 mA
Minimum Line Voltage 7 V DC
Minimum Ringing Voltage 40 V AC
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 Message-Waiting-Lamp-On code is dialed by the VPS, either the lamp on the corresponding extension should light or the extension should receive a stutter dial tone. The VPS functions best when the extension number of the mailbox subscriber follows the Light-On or Light-Off code. On some PBXs, however, the extension number is dialed first, followed by a hookswitch flash and then the On code. This presents a problem if the extension is answered before the VPS sends the hook-switch flash.
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 user-assigned extension.
This process slows down VPS performance as it dials the beeper or extension number and waits to confirm notification. The beeper or user-assigned extension notification is meant to be used for necessity, usually for mailbox owners who are often out of the office (e.g., sales people or field representatives). The only other option, without Message Waiting Notification is for mailbox owners to periodically call the VPS to check for messages.
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 on-hook) or notifies the caller that the party is busy or not available. It then gives the caller an opportunity to leave a message.
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.)
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5.1.3 PBX Requirements for Inband Integration
Follow-on ID or Called Party ID
When forwarding or transferring a call to the VPS, a PBX with Follow-on ID sends the mailbox number of the called subscriber to the VPS before connecting the caller. The VPS responds by playing that subscriber’s personal greeting. This operation is sometimes called Call Forward to Mailbox. Without this feature, the VPS cannot immediately play the called extension’s greeting message when the line is busy or there is no answer because the VPS does not know which mailbox to send the caller to.
5.1.3 PBX Requirements for Inband Integration