Serial Remote I/O Modules for RS-232, RS-422, and RS-485 Networks

Serial Remote I/O modules provide reliable signal acquisition and control via RS-232, RS-422, or RS-485 interfaces. These modules offer dependable connectivity for legacy and modern industrial systems alike, especially useful if you're handling sensor inputs, relay outputs, voltage readings or TTL signals.

Contact our team for advice on selecting the right Serial I/O module for your specific application.

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Serial Remote I/O Modules

Showing 60 of 73 Serial Remote I/O Modules items

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462M-OEM
Sealevel 462M-OEM
RS-485 Modbus RTU to 96 Channel TTL DB78F Digital I/O OEM Board
430M-OEM
Sealevel 430M-OEM
RS-232 Modbus RTU to 32 Isolated Digital Input OEM Board
462M
Sealevel 462M
RS-485 Modbus RTU to 96 Channel TTL DB78F Digital I/O Adapter
£324.00
462S
Sealevel 462S
RS-232 Modbus RTU to 96 Channel TTL DB78F Digital I/O Adapter
£368.00
530M-OEM
Sealevel 530M-OEM
RS-485 Modbus RTU to 16 Isolated Digital Input/16 Open-Collector Output OEM Board
£415.00
440M-OEM
Sealevel 440M-OEM
RS-485 Modbus RTU to 32 Reed Relay Output OEM Board
£291.00
530S-OEM
Sealevel 530S-OEM
RS-232 Modbus RTU to 16 Isolated Digital Input/16 Open-Collector Output OEM Board
£415.00
540M
Sealevel 540M
RS-485 Modbus RTU to 32 Open-Collector Output Adapter
£378.00
440S-OEM
Sealevel 440S-OEM
RS-232 Modbus RTU to 32 Reed Relay Output OEM Board
£291.00
540S
Sealevel 540S
RS-232 Modbus RTU to 32 Open-Collector Output Adapter
£378.00
520M-OEM
Sealevel 520M-OEM
RS-485 Modbus RTU to 8 Isolated Digital Input/8 High Current Form C Relay Output OEM Board
£266.50
463S-OEM
Sealevel 463S-OEM
RS-232 Modbus RTU to 96 Channel TTL Digital I/O OEM Board
£257.50
520S-OEM
Sealevel 520S-OEM
RS-232 Modbus RTU to 8 Isolated Digital Input/8 High Current Form C Relay Output OEM Board
£266.50
570M
Sealevel 570M
RS-485 Modbus RTU to 8 Analog Input – 8 Isolated Digital Input/8 Form C Relay Output Adapter
£403.00
410S-OEM
Sealevel 410S-OEM
RS-232 Modbus RTU to 16 Isolated Digital Input/16 Reed Relay Output OEM Board
£242.00
420M
Sealevel 420M
RS-485 Modbus RTU to 16 Isolated Digital Input/8 Form C Relay Output Adapter
£266.50
430M
Sealevel 430M
RS-232 Modbus RTU to 32 Isolated Digital Input Adapter
£230.00
420S-OEM
Sealevel 420S-OEM
RS-232 Modbus RTU to 16 Isolated Digital Input/8 Form C Relay Output OEM Board
£254.50
420S
Sealevel 420S
RS-232 Modbus RTU to 16 Isolated Digital Input/8 Form C Relay Output Adapter
£266.50
470M-OEM
Sealevel 470M-OEM
RS-485 Modbus RTU to 16 Analog Input/2 Analog Output – 8 Isolated Digital Input/8 Digital Output OEM Board
£452.00
450M
Sealevel 450M
RS-485 Modbus RTU to 16 Form C Relay Output Adapter
£280.00
450S-OEM
Sealevel 450S-OEM
RS-232 Modbus RTU to 16 Form C Relay Output OEM Board
£266.50
450M-OEM
Sealevel 450M-OEM
RS-485 Modbus RTU to 16 Form C Relay Output OEM Board
£266.50
470M
Sealevel 470M
RS-485 Modbus RTU to 16 Analog Input/2 Analog Output – 8 Isolated Digital Input/8 Digital Output Adapter
£465.50
450S
Sealevel 450S
RS-232 Modbus RTU to 16 Form C Relay Output Adapter
£280.00
440M
Sealevel 440M
RS-485 Modbus RTU to 32 Reed Relay Output Adapter
£304.50
463M-OEM
Sealevel 463M-OEM
RS-485 Modbus RTU to 96 Channel TTL Digital I/O OEM Board
£239.00
470S
Sealevel 470S
RS-232 Modbus RTU to 16 Analog Input/2 Analog Output – 8 Isolated Digital Input/8 Digital Output Adapter
£465.50
463M
Sealevel 463M
RS-485 Modbus RTU to 96 Channel TTL Digital I/O Adapter
£264.50
462S-OEM
Sealevel 462S-OEM
RS-232 Modbus RTU to 96 Channel TTL DB78F Digital I/O OEM Board
£340.50
470S-OEM
Sealevel 470S-OEM
RS-232 Modbus RTU to 16 Analog Input/2 Analog Output – 8 Isolated Digital Input/8 Digital Output OEM Board
£452.00
530M
Sealevel 530M
RS-485 Modbus RTU to 16 Isolated Digital Input/16 Open-Collector Output Adapter
£428.50
463S
Sealevel 463S
RS-232 Modbus RTU to 96 Channel TTL Digital I/O Adapter
£283.00
520S
Sealevel 520S
RS-232 Modbus RTU to 8 Isolated Digital Input/8 High Current Form C Relay Output Adapter
£280.00
520M
Sealevel 520M
RS-485 Modbus RTU to 8 Isolated Digital Input/8 High Current Form C Relay Output Adapter
£280.00
530S
Sealevel 530S
RS-232 Modbus RTU to 16 Isolated Digital Input/16 Open-Collector Output Adapter
£428.50
540M-OEM
Sealevel 540M-OEM
RS-485 Modbus RTU to 32 Open-Collector Output OEM Board
£366.00
570S
Sealevel 570S
RS-232 Modbus RTU to 8 x 16-bit Analog Input – 8 Isolated Digital Input/8 Form C Relay Output Adapter
£403.00
540S-OEM
Sealevel 540S-OEM
RS-232 Modbus RTU to 32 Open-Collector Output OEM Board
£366.00
410S
Sealevel 410S
RS-232 Modbus RTU to 16 Isolated Digital Input/16 Reed Relay Output Adapter
£254.50
420M-OEM
Sealevel 420M-OEM
RS-485 Modbus RTU to 16 Isolated Digital Input/8 Form C Relay Output OEM Board
£254.50
410M
Sealevel 410M
RS-485 Modbus RTU to 16 Isolated Digital Input/16 Reed Relay Output Adapter
£254.50
430S
Sealevel 430S
RS-232 Modbus RTU to 32 Isolated Digital Input Adapter
£230.00
440S
Sealevel 440S
RS-232 Modbus RTU to 32 Reed Relay Output Adapter
£304.50
410M-OEM
Sealevel 410M-OEM
RS-485 Modbus RTU to 16 Isolated Digital Input/16 Reed Relay Output OEM Board
£242.00
430S-OEM
Sealevel 430S-OEM
RS-232 Modbus RTU to 32 Isolated Digital Input OEM Board
£217.50
ADAM-4017
Advantech ADAM-4017
RS-485 to 8 Channel Analog Input Module
ADAM-4017+
5 in stock
Advantech ADAM-4017+
RS-485 to 8 Channel Analog Input Module
£168.00
ADAM-4018+
Advantech ADAM-4018+
RS-485 to 8 Channel Thermocouple Input Module – Modbus
£272.00
ADAM-4056SO
Advantech ADAM-4056SO
RS-485 to 12 Channel Isolated Sourcing Digital Output Module – Modbus
£128.50
ADAM-4118
Advantech ADAM-4118
RS-485 to 8-Channelannel Thermocouple Input Module – Modbus
£248.50
ADAM-4150
1 in stock
Advantech ADAM-4150
RS-485 to 15 Channel Digital I/O Module – Modbus
£130.50
ADAM-4080
Advantech ADAM-4080
RS-485 to 2 Channel Counter/Frequency Module
£157.00
ADAM-4168
Advantech ADAM-4168
RS-485 to 8 Channel Reed Relay Output Module – Modbus
£143.50
ADAM-4060
Advantech ADAM-4060
RS-485 to 4 Channel Relay Output Module
£117.50
ADAM-4021
Advantech ADAM-4021
RS-485 to 1 Channel Analog Output Module
£157.00
ADAM-4052
Advantech ADAM-4052
RS-485 to 8 Channel Isolated Digital Input Module
£90.50
ADAM-4050
Advantech ADAM-4050
RS-485 to 16 Channel Digital I/O Module
£88.00
ADAM-4069
2 in stock
Advantech ADAM-4069
RS-485 to 8 Channel Power Relay Output Module – Modbus
£175.00
ADAM-4019+
Advantech ADAM-4019+
RS-485 to 8 Channel Universal Analog Input Module – Modbus
£336.50
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Showing 60 of 73

Why Use Serial I/O When Ethernet Is Available?
Serial modules are simpler and often more predictable in environments with electrical noise. They suit applications where deterministic communication and minimal overhead matter more than bandwidth.

What Should You Consider for RS-485 Systems?
Check the maximum number of nodes per bus and whether termination resistors are built-in. Correct line balancing is key to keeping communication stable over long runs.

How Do They Fit into Mixed Networks?
Many serial I/O modules can be paired with protocol gateways, extending the life of older installations by linking them to modern supervisory systems.