Sigtronics EAI-Vox User Manual

Sigtronics EAI User Operation Instructions

INSTALLER: Please give a copy of this operation instructions to the users of the EAI System!

SQ ON

Squelch Control Volume Control

SigtronicsVOXIntercom

The following describes how to use the EAI System as well as adjust
the EAI controls. It also explains exactly how the EAI unit operates.
This will allow you to easily set all unit functions to your specific
needs. If you are not familiar with the EAI operation, perform the
next few steps while the vehicle is not in motion.

Headsets and Intercom

Put on the headset(s) and position the boom mike close to the
mouth, as is the practice with a hand-held mike. For best voice
clarity, the headset microphone must be positioned to one side of
the mouth and 1/4 inch from the lips. Turn the volume control on
the headset ear cup to maximum. Turn down for individual hear­ing needs if necessary only after intercom and radio volumes have
been set correctly (see below). Intercom operation and adjustment
can be performed by the following procedure:

1. Turn the intercom SQUELCH control to the maximum clockwise
position. For best system performance set the intercom VOLUME
control as low as possible. On most systems this will be approxi­mately the 10 o’clock position. Note: the intercom volume control
only adjusts the volume of conversation between the headsets
inside the vehicle. It does not affect the level at which you hear
the dispatch radio. (see Radio Operation below) You should now
hear yourself and others on the intercom.

2. To adjust the Intercom SQUELCH for voice activated operation
(VOX), it is helpful to have some background noise (truck engine
or ...). Turn intercom SQUELCH control all the way counter-clock­wise. Now, without speaking, rotate the SQUELCH control clock­wise until you hear the background noise in your headset. Next,
rotate it counter-clockwise in small amounts until the background
noise disappears. Finally, make small adjustments until your voice
triggers the unit at comfortable speaking levels. This procedure
is necessary because the squelch is a “Fast-on, Slow-off” system.
When you speak, your voice will be heard in the headsets but the
sound will cut off about a second after you stop speaking. Minor
readjustment of the squelch may be necessary if the background
noise level changes significantly (engine idling to cruise power
with siren on).

VOL

Radio Operation

With the EAI System, your radio is heard through the headsets as
well. Adjust the volume level of the dispatch radio in the headsets
with the volume control on the radio as normal. Note that the radio
volume does not effect the intercom volume and visa versa.

Transmitting (talking to dispatch) from the selected headset posi­tions is possible on a one-at-a-time basis. For a typical EAI installa­tion the Driver or Officer positions can transmit at any time simply
by pressing their PTT switch. The other positions cannot transmit
on the radio. When one position transmits, several things take place
automatically:

• All headset microphones, except for the transmitting position,
are muted.

• The radio is put into transmit mode.

• The headset microphone audio (your voice) is sent to the radio.

• Sidetone is generated and sent to your headphones.*

* Sidetone is a portion of the transmitted voice signal sent back

into your headset so that you can hear what you are saying while
transmitting. The intercom VOLUME control adjusts the volume
level of the sidetone that you hear in your headset. The other head­sets will also hear the transmission sidetone. Of course, when the
PTT switch is released, (stop transmitting) all functions return to
normal, instantly and automatically.

For Dual Radio Units - EAI-D4 and EAI-D6:

The operation of the dual radio EAI units are identical to that of the
single radio units except for the addition of radio selection:

Radio Selection of both Radio 1 and Radio 2 radios are provided
by two switches.

1. RADIO 1/ RADIO 2 (TALK) determines the radio you wish to

transmit on.

2. AUTO / BOTH (LISTEN) selects which radio(s) you receive or hear

in your headset.

a) “ AUTO” position allows you to hear the radio that the RADIO

1 / RADIO 2 switch is set to.

b) “ BOTH” position permits you to hear both the radios at the

same time.

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S

®

Specialists in “SOUND” Management

178 East Arrow Highway, San Dimas, CA 91773 ( 909 ) 305-9399

9-8-2010 eai_vox.pdf