Section 25: GSM LL/GSM/USB-3G Tab
T
ieline
Page 248
T E C H N O L O G Y
26.4.1.
POTS
Select this operation mode when connecting via a standard POTS
connection.
26.4.2.
GSM Landline
This function needs to be selected if the codec you are using is to dial via a
landline and will be communicating with another codec using a GSM cell-
phone. Only the landline-connected codec needs to select this function.
26.4.3.
Voice
Select this operation mode when connecting using a standard voice call.
26.5.
GSM Landline Pre Buffer Secs
The nature of GSM transmissions means information is sent in ‘bursts’.
Sometimes this can lead to program drop-outs. If you find you are getting
program drop-outs, you can attempt to circumvent them by delaying the time-
frame in which packets of information are received. In effect you are creating a
buffer.
1-2 seconds is usually sufficient to avoid any problems but the delay can be set up
to 9 seconds if required. Program signals will be delayed by the amount of time
set in this menu. You only need to adjust this setting if the Landline connected
codec is having problems receiving audio. If you are still getting program drop-
outs after adjusting this setting, it could be due to network congestion. Hang up
the connection and try to reconnect in a short while. (Related topic: GSM
Operation)
26.6.
GSM Landline Bitrate
The GSM landline bitrates needs to be set at the codec using a POTS
connection. This setting is only active if you have checked the
GSM Landline
Mode
box for your POTS connections. If you have not checked these boxes, the
GSM Bitrate
settings will be greyed-out.
You only need to set the
GSM Bitrate
setting if you are connecting your codecs
using a GSM and landline connection. If you are connecting two codecs that are
both using GSM connections it is not necessary to set the bit rate - this will
automatically be determined.
To determine the correct setting it is best to check the connection bit rate
possible at the codec which will be using a GSM connection, i.e. try to connect at
the GSM end and see what the connection bit rate is. Then enter the bit rate
possible at the codec using the POTS landline connection and attempt to
connect.
