GAI-Tronics 491-204 Mine Dial / Page Phone - Manual (Page 8)

Pub. 42004-195E
Model 491-204 Mine Dial/Page Telephone Page: 8 of 9
f:\standard ioms - current release\42004 instr. manuals\42004-195e.doc
04/10
Merge Mode
The system automatically transfers to this mode in the event of a switchboard failure.
1. Press and hold the handset pressbar; no dial tone will be heard.
2. Push and hold the E MERGENCY P AGE button.
3. Page the desired person(s).
4. Release the button, and wait for an answer.
N OTE : Conversations are NOT private; any number of persons may use the party line
simultaneously in the same conversation.
5. Release the handset pressbar to terminate the call.
Flashing Page-Indicator Light
Automatic circuits “answer” incoming calls and permit the calling party to page the desired person using
a self-contained horn-type loudspeaker. This voice page is preceded by a distinctive tone and is
accompanied by a flashing light to assist in locating the telephone in dark areas. The flashing light also
gives visual notice of the call in high-noise areas. The flashing light complies with Virginia and West
Virginia MSHA regulations.
The flashing light circuitry connects to the mine dial/page telephone circuitry at only four points—the
two battery binding-posts and the two loudspeaker connections. The audio signal at the speaker does not
control the light. The dc level on both loudspeaker lines, with respect to the positive battery terminal,
controls the light.
Specifications
Line voltage ...................................................................................................................................... 12 V dc
Supervisory current....................................................................................................... 20 mA dc maximum
Audio impedance, input .................................................................................................. 200 ohms, nominal
External controls (2) ............. Push-to-operate switch (in handset)/Emergency Page push button (on panel)
Internal controls (2) ..........................................................Speaker volume adjustment; sidetone adjustment
Microphone............................................................................................................Dynamic, noise-canceling
Speaker........................................................................................................................ Dynamic, horn-loaded
Power supply...............................................................................................Internal dry cell battery, 12 volts
Page-indicator Lamp (optional) ........................................................66 flashes per minute; 6.6% duty cycle