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no strong electromagnetic radiation on the BLUESTAR installation site;
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the ISDN PRI connection must be configured properly and meet ITU-T Q.931-EDSS1 or
QSIQ and related recommendations.
8.3. Potential GSM Network Problems
The BLUESTAR works reliably even under a 100% load. The following problems may be
caused by GSM networks:
1. The BLUESTAR GSM modules cannot log in, log in slowly or log out occasionally. This
problem can have two causes:
•
The GSM signal level is low – the recommended minimum signal level is
approximately -80dB, if lower, the GSM antenna location must be changed.
•
The GSM cell into which the modules try to log is overloaded – if you use directional
antennas, you can direct them to more GSM cells than one. The possibility to choose
a cell by directing your antenna is considerably limited or eliminated in municipal 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 provider. CAUTION!
You are recommended to use 32 channels at most on one installation site (one
BLUESTAR ) for one GSM provider to avoid GSM network overload problems on the
installation site.
2. One of the GSM modules is permanently logged-out or fails to receive incoming calls –
this problem indicates a GSM network overload due to heavy traffic. You can eliminate
this problem by the above mentioned solutions or extend the “relaxing time“ – i.e. the
delay between two calls via one GSM module (the recommended value is 2 seconds).
In case any of the GSM modules cannot log in the network even after reset, your GSM
provider may have located the SIM card but refused to log it in the network because
either too many calls are made using this card, or the SIM card keeps logged in the
same GSM cell and the same GSM module for too long. This problem can be solved by
occasional replacement of SIM cards between modules.
