Intel 537EX - Manual (Page 37)

536EX Chipset Developer’s Manual 37
Intel Confidential
Data Mode AT COMMANDS
Local Modem (or Test Modem)
AT&F &W Returns the modem to the factory defaults.
AT S18 = 0 &T1 Causes the modem to run local analog loopback without self-test.
CONNECT 115200 Modem response code indicates that analog loopback is
enabled with a DTE speed of 115200.
This is a test. Test string that the user could type at the keyboard. If the received data
is the same as the test string, then the DTE-to-modem communication
channel is working properly.
+++AT TIES Escape Sequence is used to return to command mode.
OK Modem enters command mode.
AT&T0 Terminates any loopback test.
OK Modem aborts analog loopback and stays in command mode.
3.9.2 Local Analog Loopback With Self-Test [AT&T8]
This test is used by the local DTE to check the DTE-to-modem communication integrity.
Figure 6. Local Analog Loopback Test
DTE
TXD
RXD
TRANSMITTER
RECEIVER
LOCAL MODEM
Figure 7. Local Analog Loopback with Self-Test
DTE
TXD
RXD
TRANSMITTER
RECEIVER
LOCAL MODEM
PATTERN
GENERATOR
PATTERN
CHECKER