The SCADALink I/O Modules are used to expand the I/O capabilities of the SMX900, IO900, IP100 and the DC100 by connecting to the I/O bus. Up to 8 expansion modules can be attached. There are 5 types of expansion modules:

Product	Name	Type of I/O
	AI4	4 Analog Inputs (4-20mA)
	A04	4 Analog Outputs (4-20mA)
	DI8	8 Digital Inputs
	DO8	8 Digital Outputs (Relays)
	A8D4	4 Analog / Digital Inputs 4 Analog / Digital / Pulse Inputs 4 Digital Outputs

Bentek Systems' I/O Modules can be attached to the SMX900, the IO900, the IP100 or the DC100 via the I/O bus as shown:

The following figure shows two I/O expansion modules, the AI4 and the DO8, connected to the SMX900: