AT&T 3B2 Off-Line Diagnostic Manual page 704

Phase Descriptions - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Phase #20 - GPSC-3B - Local SCC Interrupts
Phase Name:
Type:
Function:
Tests:
Notes:
GPSC-3B - SCC Local Interrupts (inLllp)
Demand
This phase diagnoses the receive buffer break interrupts. These can be tested
without an external loop around connector. Send a break character and check
that the proper interrupt occurred. Test for each channel on the Serial
Communication Controller (SCC).
Test 1 - checks SCC Channel A.
Test 2 - checks SCC Channel B.
This test will not stop on the first failure but will continue until all ports have
been tested. If a port(s) fails, a failure message is displayed; the other ports are
then tested.
16-32 OFF-LINE DIAGNOSTIC MANUAL