I/O refers to Input/Output, which is the transfer of data between the CPU and a peripheral device. I/O modules, which can be digital and analog, are self-contained components that interact between the CPU and peripherals.
Axis D3110 Mk II digital/analogue I/O module Analog Relay channel

Axis D3110 Mk II digital/analogue I/O module Analog Relay channel

Axis
£518.99
Axis 02861-001 digital/analogue I/O module Relay channel

Axis 02861-001 digital/analogue I/O module Relay channel

Axis
£370.99
Axis 02554-001 digital/analogue I/O module

Axis 02554-001 digital/analogue I/O module

Axis
£202.99
Axis 02553-001 digital/analogue I/O module

Axis 02553-001 digital/analogue I/O module

Axis
£148.99
ATEN 8-Channel Relay Expansion Box

ATEN 8-Channel Relay Expansion Box

Aten
£440.99
ATEN 8-Channel Digital I/O Expansion Box

ATEN 8-Channel Digital I/O Expansion Box

Aten
£440.99
APC Smart-UPS SRT Output Hardwire Kit, 5kVA

APC Smart-UPS SRT Output Hardwire Kit, 5kVA

APC
£269.99
Axis 0821-001 digital/analogue I/O module Relay channel

Axis 0821-001 digital/analogue I/O module Relay channel

Axis
£323.99
Axis 0820-001 digital/analogue I/O module Relay channel

Axis 0820-001 digital/analogue I/O module Relay channel

Axis
£688.99
HP HDMI Port Flex IO (705)

HP HDMI Port Flex IO (705)

HP
£23.99
HP Desktop Mini I/O Module

HP Desktop Mini I/O Module

HP
£77.99