Comrex DH22 Dual Digital Hybrid International

DH22 Dual Digital Hybrid for Outside Locations North America


DH20 / 22 Overview

Are you looking for the very best, most affordable digital telephone hybrid available? You just found it. The DH20 and DH22 Digital Hybrids incorporate the latest in DSP technology to provide you with the best sound and easiest installation.

The DH20 and DH22 are high quality single-line and dual-line telephone interfaces, designed to interconnect a standard telephone line and your audio equipment, allowing you the ability to send audio to and receive audio from a connected telephone line. The DH20 and DH22 are ideal when the very best audio quality is required for talk shows, news feeds, production, recording studios, and internet applications.

Our newest DSP technology delivers better and more reliable sound quality. The DH20 and DH22 deliver the deepest and most stable hybrid null, ensuring maximum isolation between the send and caller audio. That means no echo and no "bottom of the barrel" sound.

In addition, we've added selectable automatic gain control (AGC) and caller ducking. With AGC, each call will be delivered to your equipment at the same level. Caller ducking reduces the caller's audio level when the announcer speaks, providing a more "controlled" environment. We've also added a speaker amplifier so you can connect a speaker directly to the unit and monitor callers without headphones.


DH20 / 22 Features 

  • The world's best, most affordable digital hybrid
  • DSP digital technology ensures the very best audio quality and the deepest, most reliable hybrid null
  • Easy to install, simple to operate
  • Built-in speaker amplifier
  • Balanced audio in and out
  • Mic or line input
  • Selectable AGC ensures every caller is at the same audio level
  • Selectable caller ducking
  • Selectable auto-answer/auto-disconnect compatible with most telephone central offices including loop current interruption and busy/reorder tones
  • Remote control and status
  • Automatically accepts all worldwide voltages
  • Worldwide compliant, including FCC, CSA, CE and CTR21
  • Dry line capability (U.S. version only)


DH20 / DH22 Specifications



  • Caller Output: XLR male, 0dBu nominal, adjustable, balanced, 50 Ohm impedance
  • Aux Output: XLR male, 0dBu nominal, adjustable, balanced, 50 Ohm impedance
  • Telco Line: RJ-11 connector, POTS line or analog extension from a PBX or dry line (no DC offset voltage)
  • Telco Set: RJ-11 connector
  • Remote: DB-25 Female
  • Remote Send Input: 0dBu nominal, adjustable, unbalanced, 20k Ohm impedance
  • Remote Caller and Aux Output: 0dBu nominal, adjustable, unbalanced, 50 Ohm impedance
  • Control Inputs: Remotely activate any of the following functions with a switch closure to ground: On, Off, and Monitor Mute
  • Status Outputs: Remotely check the status of the hybrid using the On and Off status outputs. Status outputs are open collector outputs rated at 30VDC and 40mA maximum
  • Monitor Output: 1/4" stereo jack: Tip=+phase, Ring=ground, Sleeve=ground, 1W output into an 8 Ohm load
  • Send Input: XLR female, Mic/Line selectable, -55/0 dBu nominal, adjustable, balanced, bridging, 20k Ohm impedance


Telephone Transmit

  • Nominal send input of 0 dBu referenced to -15 dBu onto the telephone line
  • Frequency Response: 250 Hz to 3.5 kHz, ±1dB
  • Distortion: <0.1%


Telephone Receive

  • Nominal telephone line level of -15 dBu referenced to caller output of 0 dBu
  • Frequency Response: 250 Hz to 3.5 kHz, ±1 dB
  • Distortion: <0.1%



  • Caller-to-Send separation: 50 dB nominal
  • Tail time: 32 milliseconds


  • On/Off Buttons
  • Volume Up/Down Buttons

Status LEDs

  • On Status, Off Status
  • Send Audio Presence
  • Caller Audio Presence


  • Send Input Level
  • Caller Output Level
  • Auxiliary Input Level
  • Auxiliary Output Level
  • Burst Adapt Select
  • Mic/Line Select
  • Caller Boost Select
  • Momentary/Latching Select
  • Auto Answer/Disconnect Select
  • Caller Control Select (0, 6, 12, or 18 dB)
  • AGC Select
  • Auto Mix-Minus Select
  • Aux Mix Select


  • Send-to-Caller separation: 55dB nominal
  • Tail time: 32 milliseconds

Power & Physical 

  • Power: IEC Type, Auto Adjusting 100-240VAC, 2A, 50/60Hz, 30W
  • Size: 17.125" L x 10.125" D x 1.75" H (43.6 cm x 25.7 cm x 4.44 cm)
  • Weight: 6.35 lbs (2.88 kg)
  • Operating Temperature: 32-100° F (0-38° C)
  • Humidity: 0-80 percent

**DH20 & DH30 Sold Separately**