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P83676 A 

Sheet 2 of 5 

1.  Wheelock's TBH-104-LH Talkback Horn may be connected to a 600 ohm low power audio page port, if the page port allows two-

way audio.  Check with telephone system manufacturer. 

2.  If unused CO port requires talk battery to pass audio (most do), then install using a Wheelock RPS-2406 power supply as shown 

in Figure 4A.  For multi-zone applications, a Wheelock Zone Control is required as an interface. 

3.  "INH" is used only when TBH-104-LH is connected to a Wheelock Zone Control.  The "INH" wire inhibits (disconnects) talkback 

when an all zone page is initiated.  Use adjacent "GND" wire only when TBH-104-LH and Zone Control are using separate power 
supplies.  When not connected to a Zone Control, install a jumper between adjacent "GND" and "INH" terminals. 

 

PRIVACY LED INDICATOR OPERATION: 

A.  When connected to a Wheelock Zone control Module: 
 

-  The privacy LED illuminates only when the TBH-104-LH is in the talkback mode. 

B.  When connected directly to an unused CO port: 
  - The LED will be illuminated when the TBH-104-LH is in the idle state.  Occasional flicker of the LED is normal (caused by 

 sudden noise). 

  - When in the two-way communication (hands free talkback) mode, the privacy LED will be illuminated only when in the 

 talkback mode. 

 
 

SPECIFICATIONS: 

 

Parameter Min. 

Nom. 

Max. 

Units 

Supply Voltage 

-20 

-24 

-28 

VDC 

Operating Current 

--- 

250 

400 

mA 

Audio Input Level 

-15 

--- 

10 

dBm 

T & R Input Impedance 

--- 

600 

--- 

Ohms 

Switching Speed 

--- 

200 

--- 

m Sec 

Audio Output Level @ 1 Meter   One 8 ohm horn --- 

115 

--- 

dB 

              Two 

ohm 

horns 

 

---  110 

(Each)  --- 

dB 

Output 

Power        One 

ohm 

horn --- 

--- 

Watts 

              Two 

ohm 

horns 

 

---  1.5 

(each)  ---  Watts 

Talkback Reply Distance @ 50dB Ambient 

--- 

50 

--- 

Ft. 

Table 2. 

*  When 2 horns are used, they must be connected in series as shown in Figure 2A. 

 

INSTALLATION INFORMATION: 

The TBH-104-LH has been designed as a two component system to allow each component to be located so the optimum effectiveness 
of each can be obtained.  The system should not be located near noise producing equipment such as machinery, fans, air conditioners, 
etc.  The TBH-104-LH Horn should be positioned in a location that will project the paging output toward the area to be covered.  The 
horn should be mounted at least 15 feet above floor level.  The TBH-104-LH Control Unit should be located in an area with the least 
amount of ambient noise and the most convenient place for people to reply to the page.  Refer to Figure 1 and Chart 1 for suggested 
reply distances at a given ambient noise level.  Ideal mounting height for the control unit is 6 to 12 feet above floor level. 

 

When installing the TBH-104-LH, be sure to use mounting hardware suitable for the surface to which the components are to be 
mounted.  To install the Control Unit, simply mount one screw in desired location for top (key hole) tab of control unit.  Place key-
hole tab over the screw.  Secure the control unit by mounting a second screw through the clearance hole of the bottom tab, spacing the 
2 mounting screws vertically on 10.250" centers (See Figure 3).  The horn may be surface mounted by simply using the holes in the 
swivel base to locate and drill mounting holes.  The mounting base is also fully adjustable in both the vertical and horizontal planes. 

 

To rotate horn into desired position; first loosen wing nuts located on the base of horn, position horn as desired, then re tighten wing 
nuts to maintain selected position.  See Figure 4. 
 

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