C
omrex
C
orporation
66
again (the “chat” sounds heard at the beginning of a call) by clicking the
Retrain
button. You will lose audio for a longer time (approx. 7 seconds)
but the modems will completely re-equalize the connection and return
audio when finished.
Once ACCESS has dropped to a lower rate, either by rate drop or retrain
from either end, there is no way to force it to connect at a higher rate. If
you want ACCESS to try again for a higher connect rate, you will need to
disconnect the call and dial again.
There are dozens of factors that can affect the success or failure of a POTS
codec call, some within the user’s control and some not. Here’s a short list
of rules to follow for POTS codec connections:
1. Use the POTS codec on a direct telephone company line and avoid in-
house phone systems. A line used by a fax machine usually provides this
direct access. (Be sure to disconnect the fax machine before connecting
the codec!)
2. Check to see that there are no extensions or modems on the line you are
using — or at least arrange that no one uses these during your broadcast.
4. If there is call-waiting on your line, disable it by entering
“*70”
in front of
the number you are dialing.
5. If possible, try the POTS codec out at the remote site before your actual
broadcast at about the same time of day that you plan to use it. This will give
you a good idea of expected connect rates and possible line problems.
6. At minimum, connect a few minutes before airtime to assess the connec-
tion quality. Setting a MaxRate on the POTS codec, based on your findings, is
highly recommended. MaxRate usually should be set at a level or two below
the maximum unrestricted rate. This will provide a “guard band” of sorts
against noise and corruption which may cause errors on the line.
7. If operation starts to degrade after a long period of connection, it may be
that the phone line parameters have changed. These parameters are affected
by factors such as time of day, weather and geographic location. The modems
should be given the opportunity to renegotiate for these new parameters.
8. If you experience low connection rates or errors, try redialing. If that does
not help, dial from the other end. If the call is long distance, try forcing the
call to another carrier. If a good connection is found, keep that line up.
t
roubleShootIng
PotS
c
onnectIon