Specifications

Chapter 5: Installation
Connecting Off-Premises Extensions
Page 5-86 Mitel
®
5000 Installation Manual – Issue 3.0, October 2008
Connecting Off-Premises Extensions
Off-premises extensions (OPX) are remote single line DTMF stations connected to the Mitel
platform through telephone company [network provider] OPX circuits or customer-provided
circuits. The circuits are connected to Single-Line Adapter (SLA) circuits, which are connected
to available DEM-16 circuits or to T1M or T1M-2 module circuits.
Introduction
SLAs do not support visual message waiting applications. If single line endpoints equipped with
message waiting lamps are installed on SLAs, the lamps will not function. However, single line
endpoints can be configured in DB Programming to receive audible message waiting indication
tones.
OPX devices must be AC ringer-equipped. The SLA onboard high-voltage ringing adapter
(HVRA) provides isolation from the telephone company OPX circuits as required by FCC
regulations.
Each SLA can support one or two OPX stations. SLA circuits support AC-ringing single line
endpoints, fax machines, playback devices, etc.
With some OPX installations, voice volume levels may be degraded due to constraints on the
voice-frequency range inherent in the telco [network provider] or customer-provided circuit. To
increase the voice-frequency range, Mitel recommends installing a two-wire, negative
impedance repeater unit. For details, see the Specifications chapter.
The repeater unit is installed at the MDF between the SLA and the cabling to the OPX station.
For proper installation with the Mitel platform, make the following connections to the appropriate
pins on the repeater unit:
• Battery (–24 to –56 VDC)
• Ground
• System Tip
• System Ring
• OPX Tip
• OPX Ring
For identification of correct pin locations and for information about operating and adjusting the
repeater unit, refer to the manufacturer’s instructions.
Installing an OPX Station
To install the OPX stations:
1. At the MDF, terminate each telco [network provider] OPX circuit or customer-provided
circuit on the desired SLA circuit. See Figure 5-56 on page 5-140.
2. At the OPX location, terminate each telco [network provider] OPX circuit or customer-
provided circuit on the appropriate single line endpoint modular jack assembly [line jack
unit].
3. Program the station and/or trunk as appropriate in DB Programming.
4. Test for quality.