DEC VT420 - RS-232 Port Control Lines Loopback Test (25-Pin, Worldwide Model Only)

Troubleshooting and Testing 17
2.2.6 RS-232 Port Control Lines Loopback Test
(25-Pin, Worldwide Model Only)
This test checks the following control signals:
Data terminal ready (DTR)
Request to send (RTS)
Carrier detect (CD)
Data set ready (DSR)
Clear to send (CTS)
To run the test:
Use an RS-232 loopback connector, PN 12-15336-00.
1. Set up the terminal (Sections 2.2.1 and 2.2.2).
2. Connect the loopback connector to the 25-pin RS-232 port
(Figure 2–2).
3. Type one of the following sequences:
ESC [ 4 ; 6 y
ESC [ 4 ; 6 ; 9 y
Runs the test once.
Runs the test continuously.
NOTE
The continuously running test ends only if an error occurs or you
turn off the terminal. The keyboard does not make a bell tone
during this test.
If the test is successful:
1. The keyboard makes a bell tone.
2. The keyboard’s LED indicators turn off.
3. A VT420 OK message appears on the screen.
If the test finds an error:
The screen displays the following message. See Table 2–3.
VT420 RS-232 Port Controls Error -- 3