© Microhard Systems Inc.
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6.0 Configuration
6.1 AT Commands
Appendix B is a quick reference for the available AT commands; in this sub-
section are details regarding the most commonly used.
To invoke an AT command, enter Command Mode, then type
AT
<command>
[Enter]
.
A
Answer
Upon completion of tasks being done with the modem in Command Mode, invoking
this command will place the modem back ‘online’ (into Data Mode).
If changes were made to
the
modem’s
configuration and it is
intended
that
those
changes be saved to non
-
volatile memory, do so
with the AT command
’&W’ prior to placing the
modem online.
y
< command
command name >
x
Identical commands which change the modem’s unit address to
xxxxx
and then put
the modem into Data Mode.
Dxxxxx, DTxxxxx, DPxxxxx
Dial
g, G
Spectrum Analyzer
This is a very useful feature of the Nano. ATg or ATG will provide a display of signal
levels received within the operating environment and frequency range of the modem
under test. ATg averages 256 samples, ATG 16,000.
Invoking the ATg command causes the Nano to sweep the operating band and
provide a display of both the mean and peak signal levels, in dBm, found on each
channel.
The ‘graphical’ display is limited from –110dBm to –53dBm, and is in 1dB increments.
Ignore the leftmost asterisk in calculations (as below).
How to interpret the display (example):
...
ch 78 -137dBm * No signal was measured on channel 78.
ch 80 -105dBm ******... Mean signal level: -(110-5 (asterisks)) = -105dBm
...
Peak signal level: -(110-5 (asterisks) -3 (dots)) = -102dBm
For the n920 Channel 1 is at 902.4MHz, with subsequent channels in 280kHz
increments. Therefore, to calculate the frequency of channel
n
: Freq channel
n
=
902.4+ ((
n-1
) x 0.280)MHz. For the n2420, channel 1 is at 2401.6 MHz.
Also displayed is the average received signal strength for 5 channels above the ISM
bands. This area of the spectrum is used by paging networks.
