Connecting the STM17 Communications
The STM17 is available with two types of serial communications, RS-232
(STM17x-xAx) or RS-422/485 (STM17x-xRx). Each type requires a different
hardware connection for interface to a PC or other host system. The RS-232
version comes with a cable that will provide the interface to an RS-232 port
through a DB9 style connector. The RS-422/485 version requires the user to
provide both the cabling and the RS-422/485 interface. To connect the STM17
with RS-485, please read the Hardware
Manual.
Connecting to a PC using RS-232
Locate the STM17 within 8 feet (2.5 meters) of the PC. Plug the large end (DB9
connector) of the communication cable that came with the drive into the serial
port of the PC. The small end will have a 5-pin spring clamp connector. Plug
this end into the appropriate connector on the STM17. Secure the cable to the
PC with the screws on the DB9 connector.
NOTE: If the PC does not have an RS-232 serial port, a USB Serial Converter
will be needed. For more information, please read Connecting to an STM17 Using
USB in the Hardware Manual.

RS-232 Connector diagram for STM17S and STM17Q

RS-232 Connector diagram for STM17C
The RS-232 circuitry does not have any extra electrical "hardening" and care should be taken when connecting to the RS-232 port as hot plugging could result in circuit failure. If this is a concern the RS-422/485 version should be used. Do not plug or unplug the RS-232 connection while power is applied to the drive. This is known as "hot plugging" and should be avoided.