Guardian Telecom Inc.
Installation and Operation
Model ExP-TBA
Page 6
Installing the EXP-TBA
The master station is approved for use in hazardous areas. The speakers
used with the system may or may not be approved, check the labels on the
speakers for ratings.
Follow all local codes and requirements when installing the EXP-TBA Intercom
System.
Mount the Master Station and speakers.
Wire the system in accordance with local codes. The speaker cable used in the
system requires either two or four 18 AWG, shielded conductors – depending on the
system configuration. Power cable requires either two 14AWG conductors (DC), or
three 14AWG conductors (AC).
See: Figure 4 -
Typical Installation
If necessary adjustments to potentiometers can be made during commissioning to
suit existing conditions. In order to facilitate making adjustments on the circuit board
remove the faceplate, offset it to one side or the other of the enclosure and then
secure it temporarily to the enclosure with two bolts.
See: Figure 5 - Circuit
Board Layout
Post announcement tone jumper: The post announcement tone is very useful in a
half duplex intercom system. A beep-tone will be heard when the push to talk switch
is released, the tone will signify that the transmission from the master station is over.
If in PTT mode, the tone will also be heard when transmission from the slave
speaker is over. Jumper JP1 on the circuit board is used to enable or disable the
post announcement tone. To enable the post announcement tone set the jumper to
the TONE position, to disable the tone set the jumper to the OFF position.
Microphone input level Potentiometer: This potentiometer is referenced R24, and
labeled as MIC INPUT ADJ. It is used to control the audio signal from the
Microphone input and the Master speaker as microphone input.
Slave Station Talk-Back input level Potentiometer: This potentiometer is
referenced R43, and labeled as TALKBACK INPUT ADJ. It is used to control the
input audio signal from the Slave Speaker.
Ringer Volume Adjusting Potentiometer: This potentiometer is referenced R54,
and labeled as RING VOL. It is used adjust the volume of the ring tone and the beep
tone by controlling the input audio signal.
Master Station speaker Attenuation Potentiometer: This potentiometer is
referenced R21, and labeled as ATTEN LEVEL. It is used to control the amount of
attenuation to the Master Station speaker (if the master station microphone is used),
when the Push-To-Page switch is activated. It should be adjusted when the Push-
To-Page switch is engaged, to a level that will not cause acoustic feedback
(howling), with the volume control on the front of the faceplate turned to maximum.
Important: Speakers should be mounted as close as possible to users, since they
serve as microphones as well. This will reduce the amount of ambient noise
entering the speech transmission.
Apply a bead of lubricant to the machined surface of the housing.
Replace the faceplate ensuring that the connector is properly seated.
Torque faceplate bolts to 13.5 ft. lbs. (18 Newton-Meters).
Tip: The lubricant
acts as a seal to
prevent water and
dust from entering the
enclosure.
