Instruction manual

ACU-1000 Operations Manual
Interoperability Now 2-105
2.17.3.15 PSTN-2 Simplified Setup Procedure
This is a set of hints to assist in the basic setup of a PSTN module to the phone system it’s
connected to. It gives a step-by-step process that lists the steps in the best order to quickly
achieve the best results.
• Crossconnect the HSP-2A handset to the PSTN and place a call from the PSTN-2 to the
phone number of an associate who will help with the setup. Refer to Section 2.17.3.1,
Telephone Line Level. Ensure that the line levels are correct for the network being used
and do not exceed maximum allowed levels. Within the guidelines presented, the line level
may be adjusted in 3 dB steps to present the proper level to your associate at the remote
telephone. The phone line levels works inversely proportionate to one another. Setting the
PSTN to -9 dBm means the incoming audio in boosted nine decibels before it is put on the
ACU backplane and the outgoing is attenuated 9 decibels before it hits the phone line.
Following this procedure will ensure the distant user and the item connected to the ACU
will have ample audio levels.
Note the default setting of -9 dBm is the maximum allowed into most U.S. and foreign
telephone networks at the subscriber end. Some PABX’s may only allow -12 dBm
• Now listen as the associate speaks and verify that the VOX LED illuminates on the PSTN
even for softly spoken speech. If the VOX doesn’t always trip, raise the telephone RX
Level Boost setting until it does, but no higher. 6 dB of boost is the typical default setting
to start with.
• Continue to have a conversation while monitoring the VOX LED. If problems persist with
failure to VOX or if false VOXing due to background noise on the distant phone occurs,
adjust the VOX threshold as needed. There are only two settings, Low & High. The
default setting is Low threshold. If the VOX does not always trip, and the setting is
currently at High, lower the threshold to the Low setting. If the threshold is already set to
Low, the VOX cannot be made more sensitive, so the RX Level Boost must be increased.
If the VOX sometimes falses on background noise, and the threshold is set to low, move the
threshold to the high setting. Note: The VOX is expected to trip on loud background
noises; lower the threshold only if the VOX is activated for background sounds that are
below the volume of normal speech.
• Now have your associate on the distant phone count from one to twenty at a slow,
conversational rate. The VOX should remain active throughout. If the VOX drops in and
out, raise the VOX hangtime just until this no longer occurs. The default setting is one
second; if the VOX continually drops out between words, increase it to 1.5 seconds or, if
necessary, to two seconds. Change the VOX Hangtime with the ACU Controller or by the
HSP keypad.
• With the HSP handset, talk with a normal conversation level and have your associate verify
that you are being received at an acceptable level. If not, and you are outputting the
maximum legal level to the line, then contact the Raytheon factory for further suggestions.