The 12-32-0000 is a 32 input expansion module that may be used either autonomously with a serial to ethernet converter or with any transmitter that supports Salcom protocol. Input modules may be daisy chained together to provide as many inputs as required.
A simple LCD provides indication of current inputs states and system messages. LEDs provide indication of system health, upstream and downstream serial port activity. When a message is generated by an input module the content of the message will display (up to the first 16 characters) on the LCD momentarily.
The 12-32 supports multiple message queuing, and will queue at least 50 messages. Pre-defined input messages are limited to a maximum length of 40 characters which may be configured using Salcom programming software.
The input module may be configured to tag each message with a source description (e.g  or [Shed 1]).
Each input module will send it’s input message when triggered, to the downstream unit (connected to the left hand side RJ12 socket). This may be either a transmitter, or another input module. A module connected downstream will acknowledge receipt of a Salcom protocol message, so reliable delivery to the transmitter can be ensured.
The input module may be configured to operate without acknowledging, so that input modules may be connected to a PC or unit that does not support Salcom protocol (but this is not advised, since messages may be lost).
When configured to wait for acknowledgment the input module will attempt to resend the last message again with a frequency as set by the user (up to every 10 seconds – default 1 second).
When a message cannot be acknowledged (probably due to a break in a serial cable link somewhere downstream) the input module may eventually fill its message queue, and stop acknowledging messages from upstream modules. If the input module is in an error or busy state preventing the offloading of messages, the module “breaking” the chain can easily be identified by inspecting the serial traffic and error LEDs.