Clear-Com TEL-14 - Manual (Page 31)

T E L - 1 4 T W O - C H A N N E L T E L E P H O N E I N T E R F A C E 3 - 3
10.Excessive echo, background noise, or instability is heard during telephone
calls or just at the start of a call.
• The TEL-14 will usually adapt within 5 seconds of the start of a call. Before it
has adapted, voices may temporarily sound hollow. This effect is normal, but
may be minimized by reducing the send and/or receive volume settings.
• Press the Auto Gain button to light the yellow Auto Gain Adjustable LED.
Decrease the send and/or receive volume controls until acceptable operation is
attained.
• If a speaker station is used, make sure the mic gain is set low and reduce the
front panel volume level.
• TEL-14 must be made to renull the telephone line whenever it is connected to
a different telephone number. Perform the renulling sequence described in
Chapter 1.
• Set the Receive Suppression Disable option switch S6-1 to the OFF position.
This will remove noise coming in from the telephone line.
• Set the Intercom Echo Cancel and/or Telephone Echo Cancel option switches
S6-2 and S6-3 to the OFF position. Normally this is not necessary and it will
result in an undesirable reduction of trans-hybrid loss. These switches should
only be set to the OFF position if instability results in an TEL-14 to TEL-14
connection between two intercoms. Never do this to both TEL-14 lines in a
connection between two intercoms.
• Set the HDX Disable option switch S6-6 to the OFF position. This is a
drastic measure which will cure instability on poor telephone lines, but it will
do this at the expense of full-duplex conversation. In this mode, conversation
will be half-duplex unless the TEL-14 automatically detects that full-duplex
conversation is possible.
11.Sound on the telephone line causes the line to disconnect. The TEL-14
incorporates a precise call progress tone detector, so it is unlikely to sense
speech.
• If a steady sound seems to be causing the disconnect, set the Sense Dial Tone
option switch S1-2 to the OFF position.
• If interrupted sounds seem to be causing the disconnect, set the Sense Busy
Tone and/or Sense Reorder Tone option switches S1-3 and S1-4 to the OFF
position.
Refer to the following figures located at the end of this chapter:
1. Block Diagram - TEL-14 Interface