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Description
The
Bogen Model TBA15
is a 15-watt Paging/Talk Back amplifier which complies with Part 68 of FCC rules. The unit permits two-
way communication between a telephone handset, and one or more paging zones.
The TBA15 senses and automatically switches the direction of conversation from telephone to loudspeaker without the use
of relays or other moving parts. Control of speech direction is maintained at the telephone handset. Controls are provided to adjust
the switching sensitivity, switching delay, and loudspeaker and talk back (handset) volume levels.
The TBA15 has a talk back frequency response which has been shaped for maximum intelligibility and background noise rejection.
Switching delay time is adjustable from less than 50ms to greater than 0.5 seconds to ensure an intelligible flow of conversation.
A “power on” LED, circuit breaker, and volume control are located on the front panel. A recess in the panel, protected by a removable
cover, houses the 600-ohm transformer-coupled telephone line input, 25V and 70V constant voltage outputs, and muting terminals
(for one-way paging). Controls to adjust sensitivity, switching delay and talk back volume are also located within the panel recess.
The amplifier operates from a 120 volt, 60 Hz, AC source. A press-to-reset circuit breaker protects the unit from excessive current
flow. Safe Operating Area (SOA) and thermal protection safeguard the output device. The unit is finished in textured black enamel
and mounts easily on a wall backboard or in standard 19” equipment racks.
Installation
Warning: To prevent fire or shock hazard, do not expose this equipment to rain or moisture. There are no user-serviceable
parts within this equipment. Removal of the cover presents an electrical shock hazard. Have all internal service performed
by qualified service personnel.
Mounting
Avoid proximity to heat sources and strong magnetic fields. Provide for adequate ventilation for chassis heat dissipation. To eliminate
possible crosstalk interference, do not run input and output lines close together, and route through separate knockouts on the
terminal strip cover.
For
Wall-mounted installation
, set the 2 top screws 18-5/16” apart, allowing the screw heads to protrude 1/8” to 1/4”. Fit the chassis
onto the screw heads at the keyhole slots and position the two bottom screws. Complete the installation by tightening all screws
securely. For best support, use self-fastening hardware when mounting the unit to plasterboard or similar thin materials. The unit
weighs 7 pounds.
For
Rack-mounted installation
, install the unit facing into the rack. A blank panel may be used to cover the exposed rear surface of
the amplifier. Secure the unit and blank panel with the same screws.
Power and Grounding
The AC line cord is terminated in a three-prong plug, which should be plugged into a three-wire, grounded outlet. It is important
to ground the amplifier properly. “Pigtail” adapters may be used only when properly connected to a grounded outlet. A front panel
LED illuminates when power is applied to the unit.
Connections
All connections to the TBA15 are made through a screw terminal strip, located within a recess on the amplifier front panel. Keyhole
slots on the recess cover allow for quick access to terminal connections. Knockouts are provided on the cover to admit wiring.
Run input and output wiring through separate knockouts.
Telephone Line
The TEL LINE terminals are a 600-ohm transformer-balanced telephone side connection (dry signal only, no loop current). In typical
applications with a single-paging zone, this line interfaces with a station port or trunk port of an in-house telephone system (via the
Bogen Model TAMB2 Telephone Access Module, or other suitable interface) and is reached by dialing a number reserved for paging.
Loudspeakers
The TBA15 provides 25V and 70V constant voltage speaker outputs for balanced systems. Use two-conductor shielded cable with
insulation over the shield. Connect one conductor to the 25V or 70V terminal and the other conductor to the COM terminal. Connect
the cable shield to the GND terminal. The total speaker load should not exceed 15 watts.
Mute
The TBA15 may be configured for unidirectional (telephone to loudspeaker) operation, if desired, by connecting the +MUTE
terminal to the –MUTE terminal. The +MUTE terminal is a current limited (by a 1 kilohm resistor) 15 volt supply provided primarily
to control the talk back mute feature; however, it may be used to supply power to auxiliary equipment (e.g., TAMB2 external VOX
enable). The –MUTE terminal is the talk back mute control terminal. The talk back feature will be defeated if +5V DC or greater
(referenced to the GND terminal of the TBA15) is applied to this terminal.
