Connection To The External Antenna - Digicom GSM Bulk User Manual

2.3 CONNECTION TO THE EXTERNAL ANTENNA

To connect the external antenna go on as follows:
1. Turn off your GSM Bulk by disconnecting the power connector.
2. Connect the SMA male connector to the external antenna of GSM Bulk, screwing it
clockwise.
3. Place the antenna and check there is a good quality signal.
You can check the signal:
• Using a cellular phone
Insert the SIM of the GSM Bulk in a cellular phone and check the quality of the
signal.
• Through the Led STATUS (see: "Led Indicator" paragraph)
Power on the modem and verify the STATUS Led. If it is red blinking, it means the
modem is recognized by the GSM network. In this way you can check the signal but
not its quality.
Attention: even if you see the STATUS Led blinking, it may not be sufficient
for data transmission.
• Through the AT+CSQ command (see: "GSM Bulk ready to work" example)
By using this command it is possible to detect a more precise signal. Power on
GSM Bulk, connect it to a your application and send to the modem the command
AT+CSQ.
The modem will answer with +CSQ: x,y; where "x" is the signal quality, "y" is the
BER (Bit Error Rate).
The value of "x" can be included between 0 to 31; the higher value indicates a better
signal.
From 0 to 9 : poor
From 10 to 15 : good
From 16 to 31 : excellent
99 = Unknown or uncalculable
BER values higher than 2 may compromise the good operation of the device. In this
case place the antenna in a better position.
[ For further information on the commands, see the chapters "Functional Examples" and
"AT Commands ]
Attention: for better performances of the antenna, do not fix it directly to the
mechanics of the product or on metal surfaces.
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