SMT 420 Desense Utility
SMT 420 Desense Utility
----------------------------
The program SMT107.EXE allows you to to adjust your
SMT 420 Patriot's sensitivity for unstable AC line.
A special cable (diagram shown below) is required to
connect your SMT 420 to a PC serial port.
For users of SMT 280 models, a special interface box
available from Best Power is required to communicate
with a SMT 280.
- The SMT Communications interface is implemented as a
low-speed synchronous serial half duplex I/O port.
Connection to the Communications interface is acheived
by connecting a custom cable between a PC serial port
and DB9 connector on the SMT 420. Communication via
this interface on a PC is acheived through the use of
a custom-written application which uses several PC
serial port I/O lines to implement a TTL logic level
slow speed synchronous serial port.
PC to SMT 420 cable wiring diagram
----------------------------------
SMT 420 end: DB9F 9-pin female d-connector
PC end: DB9M 9-pin male d-connector, connected to
serial Com port
Cable wiring:
SMT Pin # PC Pin #
(DB9F) (DB9M)
-------- --------
1 ------------ 4
3 ------------ 6
4 ------------ 5
5 ------------ 8
6 ------------ 1
8 ------------ 7
In addition, 3 pullup resistors 3K, 1/4W 5% are required.
One lead of all 3 resistors should be connected to pin 3
of PC DB9M, and the other leads individually connected to
pins 1, 6, and 8 of PC DB9M connector.
-----------------------------------------------------------
The following procedure describes the steps for adjusting
your SMT 420 Patriot.
1) Attach male DB9 end of cable to female DB9 port
on the SMT 420.
2) Attach female DB9 end of cable to Com port 1 or
Com port 2 on your computer.
3) Place CheckUPS Suite CD-Rom disk into CD-Rom drive and
type "SMT107" to start the program.
4) Follow instructions on screen to take your SMT through
the re-programming procedure.
5) After all necessary programming changes have been made
to the SMT, exit the program.
