Westermo RM-455U-D - Manual (Page 61)

455U-D Radio Modem User Manual
Page 62 © May 2010
Using AT Commands
BER may be tested by typing AT#B (Slave Address). The sending unit will repeatedly send
pseudo-random frames, and the receiving unit will check these frames for errors. The
receiving unit returns a response message indicating how many (if any) errors were found.
The test results are displayed on the sending unit. To test Communication to slave station 13,
enter AT#B13. To test slave station 14 using station 13 as a repeater, AT#B13, 14 etc.
An example of the sending unit’s display is here.
Test Errors Extra Level TotErr TotMissed TotTest
109 0 0 -77dBm 3 0 109 kbit
Occasionally during testing, the following may be displayed:
Test Errors Extra Level TotErr TotTest
No Response
This indicated that either the request to the responding device, or the response from that
device, was lost during transmission. lost data frames do not contribute to the bit errors,
which are calculated only on the 1,000 bit frame.
The BER test will automatically end if a test time has been entered at S8 register (refer
Appendix A). If S8 has a zero value (default), the timer is inactive and the BER test will
continue until manually stopped.
When using directional antennas (YAGI antennas) this feature may be used to align the
antenna in the correct direction by selecting the peak signal level when moving the antenna.
Begin the BER test (AT#Bxxxx), and observe the signal strength indication (Level) while
adjusting the orientation of the antenna. A peak in signal level indicates optimum orientation
of the antenna.
4.4.2 Other Radio Testing - AT&Tx
To aid in the checking and setup of the 455U-D unit, diagnostic functions are provided using
the standard Hayes AT commands. To perform the tests, you will need a terminal (PC +
hyper-terminal) set-up to match the module (same character type and serial speed). Use a
RS232 cable as per section 2.4 - refer to section 3.3.1 on setting up the PC COM port.
The table below outlines the functions of the various tests:
AT&T Radio Self Tests. Allows in-field diagnostics, and factory testing.
&T0 Stop Tone Reversals.
&T1 Tone Reversals – 200 HZ modulation
&T2 Tone Reversals – 2400 HZ modulation
&T3 Tone Reversals – No modulation
&T4 Random Tone Reversals. Generates pseudo random data and sends out radio.
&T5 RSSI Measurement. Monitors the received signal strength, and displays in dBm
Most radio tests are carried out using the AT&T2 test as this is the easiest to accomplish.