REMOTE TESTS
– This feature makes possible to perform testing of remote modems, in FSK
mode, on point-to point and multipoint links with selective addressing of the remote modem.
Every modem, when is in data mode, search received data for remote loop-back command
pattern with its own (local) address. When local or own address is recognized, modem proceeds
to internal loop-back mode with RS-232 signal isolated from DTE. Addressed modem remains
it that state until carrier is lost. Other modems on the same network stay in stand-by mode
during the tests. All remote modems, in internal loop-back or stand by mode, indicate remote
test by slow PWR led blink (1sec / 1sec cycle).
Remote test command pattern on
IG202T-R38
modem is compatible with I
G202T-R38
modem
and with IG202T-R38
modems from Cegelec and consists of seven characters as follows:
0AAh 0AAh 05Ah 05Ah <remote address> 0A5h 0A5h
There may be maximum 32 different addresses (0 to 31) on one and the same network.
There are two addresses in every modem, and they may be adjusted with two AT commands.
AT&LAxx
Local
Address
– specify modem own address. Used as modem address when
in data mode. Must be saved with AT&W command in non-volatile memory to
be valid after power up.
AT&RAxx
Remote
Address
– specify address of remote modem, which will be addressed
with remote commands in command mode. After entering the command mode
remote address is initialized from non-volatile memory.
There are 4 remote test commands. All of them first issue remote loop-back command to
remote modem addressed with specified remote address. If remote loop may not be establish,
error test status is returned. When remote loop are established and test is in progress, return to
command mode may be accomplished by sending any character from terminal or PC to modem.
Also, tests 6, 7 and 8 automatically abort and return modem in command mode in case of
carrier detect failure. After returning to command mode, modem returns values of received
level in dB units, and duration of test in seconds. Also, test 9 returns bit count and bit error
during the test.
AT&TST6
Remote Sequence F
- - remote test where local modem generates the F-
frequency of the programmed channel, detected and returned by the remote
modem. Valid only in FSK mode.
AT&TST7
Remote Sequence F+
- remote test where local modem generates the F+
frequency of the programmed channel, detected and returned by the remote
modem. Valid only in FSK mode.
AT&TST8
Remote Sequence F
+
/F-
- remote test where local modem generates the F+/F-
frequency sequence of the programmed channel, detected and returned by the
remote modem. Valid only in FSK mode.
AT&TST9
Remote Sequence 511 bits
- remote test where local modem generates the PN
Sequence at programmed channel, detected and returned by the remote modem.
This test counts number of bits sent, and error bits during the test, which
indicate the bit error rate of the transmission line. Valid only in FSK mode.
IG202T-R38 User Manual v1.3
, Rev. date: 16 November, 2009
15