JK Audio TAP-1 User Manual

TAP-1

Telephone Audio + Power Interface

User Guide

JK Audio

Introduction

TAP-1 lets you attach an analog telephone to your
consumer or laboratory grade audio equipment or PC sound
card using standard RCA audio input and output jacks.
There are three jacks on the front of TAP-1. The RJ-11
"phone" jack is the electrical equivilent to the wall jack that
you would typically plug your telephone into. Technically
speaking, TAP-1 provides up to 70 milliamps of -48 volts DC
to power your telephone and then separates the telephone
audio signal into transmit and receive voice paths. This is
similar in function to the line card on a telephone company
central office switching system. The RCA jacks provide high
quality transmit and receive voice paths to your audio
equipment.

The rear panel of the TAP-1 has three adjustments which
are accessible with a small, flat blade screwdriver. The input
level adjustment controls the volume of the signal going
through TAP-1 and into the phone. The output level adjusts
the volume from the phone to your audio equipment. The
null adjustment is used to fine tune the transmit / receive
separation between the telephone and the TAP-1. This is
commonly referred to as trans-hybrid loss or echo return
loss.

Connection

1) Connect a telephone to the front panel RJ-11 jack. DO
NOT CONNECT THIS JACK TO A TELEPHONE LINE.

2) Connect a signal source (CD player, D/A converter,
signal generator...) to the input jack.

3) Connect the TAP-1 output jack to the input of your
equipment (amplifier line input, tape recorder input,
oscilloscope...).

4) Plug in the supplied AC adaptor and apply power.

5) Adjust the line input and line output volume controls to
suit your application.

2

Applications

A single TAP-1 can be used in applications such as:
+ Phone testing and evaluation,
+ Training ASR algorithms for phone line use,
+ Simulating phone based services without actual
connection to a phone line.

Input__ __Output

Computer simulating

a central office

Service Simulator Example

3