atcomsystems.ca/forum Forums TDM Business Telephone Systems Mitel Telephones & Systems Mitel 3300 - Bad Ports

Does anyone have the voltage specs. for a Mitel 3300 ONS card.
We have a hotel customer who keeps burning out ONS ports.

It is not due to the defective card problem.

We have two phones hooked up to each port, an analog desk set and an analog cordless (Teledex).

There also are ADSL modems in each room for internet. We suspect the modem may be causing the problem.

What we want to do is test the circuits with a meter to see if the modem or cordless phones are bleeding voltage back to the circuit board.

We need to know the following:

Voltage on idle line, voltage on in-use line,voltage on ringing line, and voltage with active MW on.

Does anyone have the specs. for this?

From the tech hand book!


ONS/CLASS Line Card Specifications
The ONS/CLASS Line Card supports the Message Waiting feature. A high voltage (-140 Vdc)
is applied to the Ring terminal of the line to light a neon lamp on the subscriber’s set.
OPS Line Card (North America Only)
The OPS Line Card contains six off-premises line circuits. An Off-Premises (OPS) line circuit
is used where the line goes outside the building that houses the PBX and the line may be
exposed to extraneous high voltages or induced currents.
Number of Circuits per Card: 12
Loop Detector Threshold: 15 mA (+1 mA)
Trip Battery Ringing Interval: -48 Vdc nominal
Bridged Ringers: 5 (C4 or equivalent)
PCM Coding: μ-law
External Loop Resistance 600 ohms
External Wire Resistance 400 ohms
Power Consumption 9.09
Message Waiting Yes. A high voltage (-140 Vdc) is applied to the Ring terminal
of the line to light a neon lamp on the subscriber’s set.
Calibrated Flash No
Nominal Ringing Voltage 80 Vrms
@ 20 Hz
External Loop Length: 1500 m (4875 ft), 26 AWG (27 IWG)
3800 m (12350 ft), 22 AWG (23 IWG)
Nominal Trip Battery
Silent Interval
-27 Vdc
Features Provided: 2-wire/4-wire conversion
Line protection
Positive disconnect
Analog-to-Digital / Digital-to-Analog conversion (u-law)
Line circuit status monitoring
Signaling (ringing, message waiting)
Calling party ID data to the set while the set is in an off-hook or in an
on-hook state.
Compliance to Standards: The ONS CLASS line card (NA) supports ONS CLASS sets (NA) that
meet the following specifications:
• ANSI/TIA/EIA-716 Standard "Telecommunications
Telephone Terminal Equipment - Type 1 Caller Identity
Equipment Performance Requirements"
• ANSI/TIA/EIA-777 Standard "Telecommunications
Telephone Terminal Equipment - Type 2 Caller Identity
Equipment Performance Requirements

Thanks, I appreciate the info.

Will let you know how we make out.