EFJohnson 761X, 764X service manual Controls and Display, Transceiver Back Panel, Basic Operation

OPERATION

3.2 CONTROLS AND DISPLAY

3.2.1 FRONT PANEL CONTROLS

Power Switch ( ) - Press this switch to turn power on and press and hold it to turn power off. The trans- ceiver may be programmed so that a password must be entered to allow operation. Refer to Section 3.3.2 for more information.

Volume Up/Down Keys ( ) - Adjust the vol- ume level up or down in up to 32 steps. The minimum selectable volume level can be set as described in Section 3.3.3.

Up/Down Keys ( ) - These keys may be pro- grammed to select the next higher or lower channel or for other functions. Refer to the descriptions in Section 3.5 for more information.

Microphone Connector - Connection point for the microphone. Do not connect microphones other than standard microphone P.N. 589-7600-020 and DTMF microphone P.N. 589-7600-022 to this transceiver. The pin assignments could be different and damage to the microphone or transceiver may result.

F1/F2/F3/F4 - These keys can be programmed to con- trol any of the functions described in Section 3.5. Place the applicable included label on the switch to indicate its function.

3.2.2 DISPLAY

Transmit Indicator ( ) - Indicates that the trans- mitter is keyed or the 5-tone code is being sent (if appli- cable). If this indicator is flashing, the internal temperature is high and the transmitter power output is being cut back. Normal operation automatically resumes when the temperature returns to the normal range.

Busy Indicator ( ) - Indicates the currently selected channel is busy (see Section 3.4.4).

Bell Indicator ( ) - Appears or flashes when a 5-tone call is detected that the transceiver is programmed to receive.

Monitor Indicator ( ) - Indicates that the monitor mode is enabled. This mode disables coded squelch control so that all messages occurring on the channel are heard. Refer Section 3.4.4 for more information.

Display - This seven-character display indicates the selected channel, status information, and error condi- tions. If information in this display begins flashing, an error condition is indicated. Two possible causes are a defective antenna or a battery voltage below 8 VDC.

3.2.3 BACK PANEL

External Speaker Jack - Miniature phone jack for connecting an optional 4-8 ohm external speaker. The internal speaker is automatically disabled when a speaker is plugged into this jack.

Antenna Jack - UHF-type jack for connecting the antenna.

DC Power Cable - Connects the transceiver to a nom- inal 12 VDC, negative ground vehicle power source. Refer to Section 2-1for more information.

Accessory Cable - This optional cable is used to con- nect accessories such as a horn alert and modem to the transceiver. Refer to Section 2-1for more information.

Ext Speaker	Antenna
Jack	Jack

DC Power

Optional	Cable
Accessory Cable

Transceiver Back Panel

3.3 BASIC OPERATION

3.3.1 TURNING POWER ON AND OFF

When power is turned on by pressing the POWER switch, a tone sounds and an opening mes- sage is displayed if programmed. The transceiver is

November 1998
Part No. 001-7600-001	3-2