Page 3.5
Chapter 3
Fault Diagnosis
SCHILLER AT-2plus 6-Channel ECG Unit
SERVICE HANDBOOK Issue d May 2002
RS-232 Test with Test Plug
The communication circuits on the RS-232 interface board can be checked by transmitting a
signal and sending the signal ditectly back to the unit via the test plug. To carry out this test
proceed as follows:
Note:
If the SCHILLER test plug is not available a test plug can easily be fabricated from
a standard 9-pin D-type connector (female). Shortcircuit the following pins:
•
pins 2 and 3 (receive / transmit)
•
pins 7 and 8 (RTS / CTS)
•
pins 6 and 4 (DSR / DTR (ready))
1. Connect the RS-232 test plug (part number to be assigned) to the RS-232 port on the side
of the unit.
2
Switch the unit ON.
3. Select communication test by entering :
ALT - 0 - 3 - 7
4. Press the key
R
(receive). No output on the screen.
5. Press the key
T
. A string of characters are transmitted and will be visible on the screen.
6. You can also press
S,
whereby one single character (U) is sent over the test plug.
7. Press
Q
to quit the test and the patient key to return to ECG display.
