The DHY-04T 1U rackmount twin telephone hybrid is an improved redesign of the DHY-03, the world's best telephone hybrid. It now features auto-detecting combined analogue and AES/EBU inputs and outputs, front panel speed-dial buttons, and an Ethernet interface allowing access to internal configurations and settings via a web browser. All while maintaining impressive line balance rejection figures. For the best audio communications you'll ever hear, you should choose the DHY-04.


The unit's main new features include:

- Auto-detecting combined analogue or AES/EBU XLR input.
- Accepts AES/EBU sample rates up to 24 bit/96kHz.
- Configurable analogue or AES/EBU XLR output.
- Ethernet port for remote configuration via web GUI interface.
- Remote dialling and hold control via Ethernet.
- Ethernet network interface can generate SNMP Traps for SNMP management systems.
- DTMF tone recognition for reporter remote access - a journalist can call the unit which can recognise a pre-programmed DTMF digital password to automatically connect the journalist to air.
- Four front panel speed-dial buttons to dial internally preset telephone numbers.
- Front panel redial button to redial the last number.


The DHY-04T also has the following features:

- Fully automatic - adapts to varying line conditions and has automatic signal limiting.
- Fully adaptive echo cancellation up to 127ms - default 24ms.
- Typical line balance rejection of 76dB giving superb performance and crystal clear audio.
- Front panel input and output gain controls.
- Front panel LED indication of receive and send signals.
- Built-in conferencing for 2 hybrids, allowing a single telco channel on a mixing console to receive 2 calls.
- Built-in ring detector - automatically answers calls after a predetermined number of rings.
- Automatic call disconnection. Fitted with K-break detection, line polarity reversal and disconnect tone detection, defined by country selection.
- Auto-ducking function allows talent to 'talk-up' or talk over a caller by reducing the caller's signal gain if it exceeds a certain level.
- Local and remote line hold switching - calls can be remotely switched via a mixing console.
- Line hold/release button to control the hold circuit, illuminates to show line status and flashes to show ring status.
- DTMF tone recognition allowing opto-isolated GPI output on receipt of selected DTMF tones, e.g. to automatically start a studio automation recorder to record a remote telephone interview.
- International operation with built-in configurable settings for each country. Country selection enables the unit to provide a line impedance and simulation circuit matching the country.
- RS232 serial port for remote TBU control and DTMF dialling.
- Remote port distributes remote line connect switch and tally output, a momentary/latching selector and DTMF detect output.
- Remote line connect switch can be momentary or latching in action.
- Balanced mic/line input - 10k balanced input selectable for 0dBu clean feed line, or microphone level with adjustable gain.
- Balanced output - 0dBu low impedance balanced output, with output gain adjustment.
- Record output - conference output can be jumper set to give a mix of caller and mic/line input signals for recording both sides of the telephone conversation.
- Line limiter, bandpass filter and output noise gate with preset threshold providing low distortion audio.
- Universal built-in power supply between 90V AC and 250V AC, 47-63Hz, IEC mains input.
- Compliant with ETSI approval to European PTT specifications.