Simplex 4010-9918 | DUAL RS232 Module The Simplex 4010‑9918 Dual RS‑232 Module is an optional communication interface module designed for the Simplex 4010ES (and related) fire alarm control panels. It provides two independent RS‑232 serial ports for external device integration such as printing, service tools, or remote monitoring. The module occupies one block of the internal block‑space of the control panel, and it draws a supervisory current of about 60 mA. It is UL/ULC listed and is intended to be fitted inside the main panel chassis; wiring connections are via a pluggable harness to the panel’s internal RS‑232 interface points.