The HB-704 is a four-channel-selectable, full-duplex headset station, able to be mounted into a wall or other surface.

Optional 4-wire and TW daughter boards.

Momentary/Latching Talk switch with LED

Microprocessor controlled logic and switching

Visual call signaling

Headset connector with volume control and sidetone adjust

Optional 4-wire or TW daughter boards for flexibility

Mountable into a standard US two-gang outlet box

Headset Microphone Input

Input Type : Dynamic

Input Impedance: >= 1K

Mic Limiter Threshold: -2dBu ± 3dB

Mic Limiter Range: >= 15dB

Program Line Input

Input Impedance: >= 5K

Headset Output

Load Impedance: >= 8

Output Impedance: <= 25

Output Limiter Threshold: +5dBu ± 3dB

Maximum Output Level before Distortion: >= 17dBu

Party-line Output

Off Noise: < -74dBu

Output Impedance: >10K

Party-line Input

Crosstalk: < -60dB

Max level before Clipping: >= 12dBu

Frequency Response

Headset Mic - Party-line: 300 - 15KHz ± 3dB

Party-line - Headset Out: 300 - 15KHz ± 3dB

Max Distortion

Headset Mic - Party-line: <= 0.5%

Party-line - Headset Out: <= 0.2%

Noise

Headset Mic - Party-line: < -70dBu

Max Gain

Headset Mic - Party-line: 41dB ± 2dB

Party-line - Headset Out: >= 34dB

Power

Input Voltage Range: 20-30 VDC

Input Current (Idle): <= 50mA

Input Current (Max): <=100mA

Internal Adjustments and Connections

Intercom Line: Seven terminal connector

Option Switches: Two DIP switches

Option Board Jumper: Two sets of options jumpers

Front Panel Connectors

Headset: (1) XLR-4M

Front Panel Controls & Indicators

(1) Sidetone control

(1) Talk button

(1) Call button

(1) Channel select switch

(1) Volume control

Environmental

32 - 122F (0 - 50C)

Dimensions

4.625 in. W x 4.5 in. H x 1.75 in. D

(117 mm x 114 mm x 44 mm)

Weight

0.46 lbs. (0.21 Kg)