3.1 GUIDELINES FOR INTEGRATION
INTEGRATING THE VPS WITH PANASONIC KX-T PHONE SYSTEMS 43
The VPS must also have access to certain PBX features. For example, if the VPS takes a
message, one way it can notify the mailbox owner is by dialing the PBX's Message-Waiting-
Lamp-On code. Once new messages are retrieved, the VPS dials the Message-Waiting-Lamp-
Off code for that same mailbox owner.
3.1.4 PBX Requirements for Integration
The PBX must have certain capabilities and features to work with the VPS. (Although this
section includes tests to help you evaluate the PBX, it may be necessary to refer to the PBX's
documentation for detailed capability and feature descriptions.)

Single Line (Tip/Ring) Port Circuits

The VPS can only be connected to a PBX that supports SLT sets. Some PBXs need an OPX
card to provide this connection. However, some OPX car ds do not pro vide al l the capabi lities
listed in this section.
Following are the minimum current and voltages that the PBX must supply:

Station to Station DTMF Signaling

For system users to access VPS services and features, they must be able to send DTMF tones
from their telephones to the VPS port. As a general rule, SLT sets can perform station-to-
station DTMF signaling; however, many proprietary telephones cannot. Some PBXs need to
be programmed to make proprietary se ts use DTMF signaling.
If the PBX does not provide station-to-station DTMF signaling, VPS services and features
will be limited.
DTMF Tones
Tabl e 9
Minimum Loop Current 20 mA
Minimum Line Voltage 7 V DC
Minimum Ringing Voltage 40 V AC
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.
Tabl e 8
VPS/PBX COMMUNICATION