JK Audio Universal Host User Manual

Universal Host

Desktop Digital Hybrid

User Guide

JK Audio

Introduction

Universal Host will allow you to send and receive audio through
your multi-line PBX, ISDN, VoIP or analog telephone. While this
may seem like a simple task that any telephone can do, the
challenge is getting the best quality audio from such a limited audio
path. The USB feature will function as a remote sound card when
connected to your computer, eliminating the need for another audio
interface with more cables and level adjustments. No additional
software drivers are needed for the USB audio interface.

What is a Digital Hybrid?

The Universal Host digital hybrid connects audio signals to and
from the handset side of a telephone without the variations in
quality found with analog hybrids. The main function of a hybrid is
to bring in the caller’s voice from the phone line as clear and clean
as possible. In the real world, when you send your voice down the
telephone line it has a tendency to bleed over into the caller’s
audio. The hybrid must adapt to the audio signals from the
telephone in order to properly separate transmit and receive audio.
We use a 16 bit DSP (Digital Signal Processor) to continuously
monitor the phone line and local audio signals to deliver excellent
trans-hybrid loss, also known as separation. Our dual-convergence
algorithm can achieve excellent separation, typically exceeding
50 dB.

Ready to go?

The Universal Host controls and connectors are clearly marked
and ready for operation. The Features diagrams and Operation
sections on the following pages will help you pinpoint any minor
questions that you may have. If this is your first exposure to a
hybrid, we suggest that you read the entire manual to allow you to
take advantage of all these features.

Any Questions?

Before you pick up the phone... Please thumb through the rest of
this manual. You might find those deep technical questions are
covered on later pages.

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Features

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1. Handset Button - Press this button to use the handset as if you
were on a normal telephone call.

2. Online Button - Press this button to disable the handset and
activate the Universal Host for use as a digital hybrid.

3. Send 1 Level - Adjusts the signal level that you are sending
down the telephone line, through the female XLR input.

4. Send 2 Level - Adjusts the signal level that you are sending
down the telephone line, through the 3.5mm mini jack input.

5. Caller Level - Adjusts the level of the signal coming in from the
telephone line, as it is going out the output jacks.

6. Headphone Level - Adjusts the signal level coming from the

3.5mm front panel headphone jack.

7. Hybrid/USB - Selects audio heard at the headphone output.

8. Headphones - The 3.5mm stereo headphone jack contains
either a mix of both the Send input audio and the Caller audio
when the button is in the Hybrid position or stereo audio from
the USB port with the button in the USB position.

9. ON LED - Lit when you are on line with a call using the hybrid.

10. Send LEDs - Displays the signal level going to the phone line.

11. Power LED - Lit when unit is plugged in and receiving power.

12. Receive LEDs - Displays the signal level coming from the
telephone, after the DSP. This signal level will not change
when you adjust the Caller knob.

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Features (continued)

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12. Handset Jack - Connect your telephone handset to this jack.

13. Phone Jack - Connect this jack to the handset jack on your
telephone using the supplied handset jumper cable.

14. Handset Type Selector Switch - Use this switch to select the
correct type of handset microphone that your telephone uses.
A=Electret, B=Carbon, C=Dynamic

15. Caller Output - Male balanced XLR output contains only the
caller’s voice.

16. Send 1 Input - Female balanced XLR input for audio going into
the phone line. Mic or line level input.

17. Mic / Line switch - Sets the front end sensitivity of the Send 1

XLR jack. Set to Mic if you intend to connect a dynamic
microphone directly to the Send 1 jack. Set to Line if you are

connecting to the output of a mic mixer.

18. USB port - for bi-directional audio connection to your computer
or other equipment.

19. Send 2 Mono Input - 3.5mm mono mini jack input for signals
going into the phone line. Line level.

20. Stereo Output - 3.5 mm stereo mini jack output contains Send
and Caller audio determined by the Send 1 and Send 2 levels
and the Caller level controls. Left channel contains your local
Send audio mixed with audio from the USB connector and
right channel contains the Caller's audio from the phone line.

21. Power Jack - For connection only to the supplied 9 VDC
regulated power supply only.

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Connection

For a direct connection to Universal Host:

• Handset cable - Connect the supplied RJ-22 handset cable

between the jack marked "Phone" on the back of Universal Host
and to the handset jack on the base of your telephone.

• Handset - Connect your telephone handset to the RJ-22 jack on

the back of the Universal Host marked "Handset".

• Send Audio - Connect a dynamic microphone cable to the Send

1 jack on the Universal Host. Be sure to set the Mic/Line switch
to the “Mic” position.

• Connect the USB port to your computer or other device to either

bring additional local audio into the hybrid or deliver live audio
out for recording or streaming.

• Output - Connect a stereo cable from the mini jack “Stereo Out”

on the Universal Host to the “Line Input” on your desktop PC
sound card, mini disk recorder or other equipment.

• Power - Connect the supplied DC power supply to the back of

the Universal Host and then to an AC power outlet.

• Place a test call to a quiet location. Set the “A-B-C” switch on

Universal Host for best audio. Set the “Send” level control so
that while you are speaking into the microphone, the Send LEDs
on the hybrid light the -20 dB green LED consistently and flash
the -9 dB green LED. If you flash the -3 dB red LED, lower the
level. Set the “Caller” control for good recording level of the
caller audio at the output jack.

Set to
“Mic”

Portable
recorder

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