15
© Sealevel Systems, Inc.
SeaI/OUSBSERIAL | SL9177 04/2022
SeaI/O Pass-Through Connector
All SeaI/O USB serial expansion modules include an RS-485 pass-through connector on the left side of the unit
that is internally connected to the same pins on the removable screw terminals. This offers two convenient
options for adding SeaI/O digital and analog expansion modules. The image on the following page shows the
pass-through connector and removable screw terminals.
For connecting several SeaI/O modules together in a “stack,”
all N-series expansion modules ship with an
expansion and strap kit (Item# KT122) that includes four metal straps, four #4-
40 screws, and a 5” RJ45 RS
-485
interconnect cable (Item# CA239). The metal straps allow you to securely connect multiple SeaI/O modules
together. The interconnect cable can be used to connect SeaI/O modules together via the RJ45 pass-through
connectors, providing an easy method to cascade RS-485 signals and power from one module to the next.
For expansion modules that are less than ten feet from a base unit, a standard RJ45 CAT5 patch cable may be
used. For SeaI/O modules greater than ten feet apart, use twisted-pair cable connecting the data lines to the
screw terminals instead. If RJ45 connectors are preferred, be sure to connect only the data lines (pins 4 & 5).
Modules greater than ten feet apart must have separate power supplies. Refer to the
chapter of this manual for recommendations.
