The Innkeeper 1rx Digital Hybrid from JK Audio is housed in a single rack-space chassis. The main function of a hybrid is to extract a caller's voice coming in on a phone line, while keeping it separate from the receiver's outgoing audio. Both these streams can then be controlled in various ways. A digital hybrid provides audio that is clearer and cleaner over the variation in quality found in analog hybrids. The unit functions with both "wet" and "dry" (PBX) phone lines; dry line installation is always a custom configuration, requiring substantial telephone system knowledge.
In order to achieve the required separation, an internal digital signal processor (DSP) continuously monitors both the phone line and audio signals The proprietary echo canceller algorithm can achieve excellent separation, typically exceeding 50 dB without any additional setup. Signals can be monitored from the front-panel headphone output, with a choice of the caller's voice, the sender's signal, or a mixture of both. This output is also at the rear panel screw terminals, to which an external monitor speaker can easily be added.
An auxiliary telephone jack is provided that can be used to initiate or screen calls. It is disconnected when the "Call" button is depressed, and reconnected when the "Drop" button is pressed. The unit features send and caller volume controls (hidden behind an access panel). Caller ducking drops the caller output level by 9 dB whenever the host speaks, allowing the host to remain in control of the show. Additionally, automatic gain control (AGC) keeps the caller volume at a steady, average level.
A "Presence" button engages a digital filter that boost the low frequency content of the caller's signal, enhancing the quality of the transmission. A test tone generator sends a 1 kHz full-level tone either down the phone line, or out the caller XLR jack, and can be useful in setting levels. Applications for the Innkeeper 1rx include telephone interviews, talk shows, church PA interface, and conference room full-duplex communication.