2N StarGate/BlueTower v5.3 User Manual

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is overloaded. If you use directional antennas, you can direct them to more
GSM cells than one. The possibility to choose a cell by antenna directing is
considerably limited or eliminated in towns or densely populated areas
where multiple signal reflections occur. It is also difficult to select a cell
where the cells lie in a straight line before and behind the antenna. If no
selection can be made, you have to use another available GSM / UMTS
provider.

Caution

You are recommended to use 32 channels at most on one
installation site for one GSM / UMTS provider to avoid wireless
network overload problems on the installation site.

Some wireless modules are permanently logged–out from the network or
fail to receive incoming calls:

The problem indicates a wireless network overload due to heavy traffic. You
can eliminate this problem by setting the GSM basic parameters – Call

parameter in the web interface to '2 seconds'. This parameter

delay
extends the delay between the end of one call and the start of another call
made via one and the same wireless module.

Some wireless modules cannot log in to the wireless network even after
reset:

Your GSM / UMTS provider may have located the SIM card, but refused the
login to the wireless network because either too many calls are being made
using this card, or the SIM card has been logged–in to one BTS for too
long. This problem can be solved by an occasional exchange of SIM cards
between wireless modules.

The manufacturer cannot be held responsible for any SIM card or service blocking
problems of the GSM / UMTS provider caused by the GSM / UMTS provider's breach of
a SIM card term agreement.

DTMF transmission is not correct. Some numbers are not correctly
recognized by called / calling party:

DTMF tones (as all voice services) change codec during transfer to GSM /
UMTS network voice channel (this codec change caused partially
information lost which depends on used type of GSM/UMTS codec in
wireless part of the network). To improve success rate of transferred tones,
please check audio quality / level of called + calling party ; audio settings
of opposite party; change source of DTMF tones (different length and
volume can improve probability of successful DTMF transmission) or use
DTMF transfer not in voice channel, but in signaling channel (regarding RFC
XXXX). Refer to the

subsection

Gateway Control - GSM Basic Parameters

for small changes in audio levels.

Note

Settings of GSM network and opposite called / calling party can
involve DTMF transfer. 2N cannot guarantee successful DTMF
transmission with using 2N GSM/UMTS gateway with PRI ISDN
interface (where only voice channel transport of DTMF is
allowed).