User Manual

Operation (continued)

Send Signal Level

The Send LEDs display the signal level as it goes out to the phone

line. The goal is to drive the phone line at high enough levels to

avoid phone line noise, but not so loud as to cause excessive clip-

ping. Adjust the Send level control so that you rarely see flashes of

the red -3dB peak Send LED. These flashes should occur only dur-

ing loud speech bursts. If the red LED stays lit for extended periods

you can assume that much of your speech is being clipped or dis-

torted. In this case you should decrease the Send volume control

for the input that is causing the clipping.

Caller Signal Level

The Receive LEDs only display the strength of the signal coming in

from the phone line just after the DSP. The Caller level control

does not change what you see on these LEDs. Adjust the Caller

level for the best signal at the output jacks of innkeeper PBX.

A-B-C Selector Switch

Use this switch to select the correct type of handset microphone

your telephone uses. A=Electret, B=Carbon, C=Dynamic. Trial and

error seems to work best in determining which handset type to use.

Your innkeeper PBX will only function correctly if the handset type

selector switch is in the correct position. This switch changes sig-

nal level, impedance, and wiring to accommodate the differences

in handset microphone types. To determine the correct position,

you should place a call to another telephone line, then try to send

audio to the phone line through the input jack of the innkeeper

PBX . While doing this, switch between the three different handset

type positions. Choose the position that works best by monitoring

the audio quality and Send LEDs.

Although not conclusive, the following guidelines may help:

The majority of newer telephones have electret type microphones

and will use the "A" position.

Older telephones that have the round "screw type" handsets con-

tain carbon microphones and use the "B" position.

Many Radio Shack

, Panasonic

, and Nortel

telephones have

dynamic microphone types and use the "C" position.