Local Analog Loopback With Self-Test - Epson ESC/VP21 User Manual

4.2 Local Analog Loopback with Self-Test

The local analog loopback with self-test checks the integrity of the local modem.
In this test, an internally generated data pattern of alternate binary ones and zeros
(reversals) at the selected bit rate is looped through the internal analog loop inside
the local modem to an internal error counter as shown in Figure 4-2. An error count of 255
indicates that 255 or more errors were detected.
Example - The test timer is disabled and 12 errors are found during the test
Fig. 4-2 Local Analog Loopback with Self-test
Command:
Result:
56
AT\N1<CR>
ATS18=0&T8<CR>
cursor shifts down one line (test starts)
TESTING - 4