Signet 1ZDM Operation & Instruction Manual

Page 1 of 4 DocNo.DCP0001330 RnB 25/02/04 rev2

Operation Instruction Manua

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1ZDM

Single Zone Desk Microphone

Features

The 1ZDM has compressor, noise gate, equalisation
controls and optional chime (one to three note).

The unit is fully monitored and complies with BS5839 part4.
Simple operation by the use of a single button Speak bar.
The unit is supplied in a sturdy plastic desk mounting case

with a gooseneck microphone fitted.

Technical Description

Microphone signals are passed to a voltage controlled
amplifier under control of a signal derived from rectifying
the stage output signals, providing 3:1 compression ratio.

The output of this stage is fed to an LED output level
display and a three-band equaliser (100 Hz, 1KHz, 10 kHz).

Power is supplied at nominal 24 VDC via separate cabling,
the phantom power on the audio + and audio - being used
for fault detection only. A regulator circuit provides 15 VDC
for powering the 1ZDM electronics.

Front Panel Features

The 1ZDM provides for the following LED indications:

Name Function / Description

1

OK GREEN when no fault detected.

2

FAULT AMBER when fault detected.

3

SPEAK GREEN when system ready for paging announcement, FLASHING GREEN when system is

busy.

4

VU VU meter to show audio level. VU meter is constantly active and will light in sync with audio

peaks to indicate that the audio path to the input stage is intact. This occurs even when speak
bar is not pressed.

Block Diagram

Page 2 of 4 DocNo.DCP0001330 RnB 25/02/04 rev2

Installation

Unpacking Upon receipt of shipment, please inspect for any damage incurred in transit. If damage is

found, please notify your local representative and the transport company immediately. State date, nature of
damage and whether any damage was noticed on the shipping container prior to unpacking. Please give the
waybill number of the shipping order.

The unit should not be placed in areas;

1 with poor ventilation
2 exposed to direct sunlight
3 with high ambient temperature or adjacent to heat generating equipment
4 with high humidity or dust levels
5 susceptible to vibration

Operation

The 1ZDM has been designed to offer a simple microphone input to the network, with the choice of either local
operation or global all call operation. This function is selected on set up of the network system. This unit can
also be used in the SigNET LinX voice alarm systems.

The microphone console comprises of a gooseneck, microphone, speak bar, VU Meter, and two status
indicators, one for OK and one for fault.

In order to page, the thumb switch on the microphone or the speak bar are pressed, and if the system is able
to accept paging, the speak bar will light solid green and paging may commence.

The speak bar LED indicator will flash if there is a busy input indicating that an equal or higher priority input to
the system is in use on one of the selected zones, or that access to one of the selected zones is excluded. If
the zone selection is valid, the busy in will permit the speak bar to illuminate steadily and the announcement
can be made.

Fault monitoring

The electret microphone capsule is monitored for impedance and current absorption. Any deviation from pre­set windows triggers the monitor circuit with the following results:

1. The OK LED is extinguished and the Fault LED illuminated.

2. The monitor circuit removes the 6K8 termination of the PTT. This puts an open circuit condition on the
PTT line, signalling a fault to external control equipment.

The audio lines are monitored by the phantom detect circuit which notifies any loss of the 15V phantom (due to
an open circuit or short circuit line) to the monitor circuit. The monitor circuit causes an open circuit condition
to be set on the PTT, signalling a fault to signalling a fault to external control equipment.

DC power operation

The 1ZDM requires a 24V DC supply which enters the unit through the six core cabling (see page 5).

Caution

This unit must never be directly connected into a 230V AC power supply.