The Gentner DH22 (now under the Comrex brand) is a crucial tool for integrating standard analog telephone lines (POTS/PBX) with professional audio equipment like mixing consoles. It utilizes state-of-the-art 16-bit DSP technology to actively cancel echo and provide a deep, stable "hybrid null," which results in maximum isolation between the audio being sent to the caller (send) and the audio received from the caller. This process eliminates the "bottom of the barrel" sound often associated with standard phone calls in a broadcast setting, making the caller's voice sound as if they are in the studio.

Key features designed to enhance usability and audio quality include selectable Automatic Gain Control (AGC), which maintains a consistent caller audio level, and caller ducking, which automatically reduces the caller's volume when the announcer speaks. The unit also has an integrated 1W speaker amplifier for direct monitoring of callers without headphones and an automatic mix-minus feature for simplified console integration. Housed in a durable 1U rack-mount chassis, the DH22 is ideal for talk shows, news feeds, production studios, and recording applications.