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CAS24: Code Activated Switch for Async RS232 to RS485 or RS232 to RS422 Networks


CAS24 with Box

CAS24 Label

"Let me spin a very large
RS485 network for you!"

  • Code activated switch for RS485 (2-wire, half-duplex) or RS485/RS422 (4-wire, full-duplex) multi-drop networks, using non-addressable RS232 target/remote devices.

  • Network multiple RS232 devices over either RS485 (2-wire) or RS485/RS422 (4-wire), at distances up to 4000 ft. and data rates up to 115.2Kbps.

  • Software/hardware configuration of "Node address," Data rate, Parity, "Attention character," Unit address, time-out value, and operating modes.

  • Think of the CAS24 as an addressable interface converter that can communicate with RS232 devices using the same and/or different protocols/command structures.

  • Other CAS models available with multiple ports - please call for information 513-874-4796 or 513-638-0228

General Description:

The CAS24 "Code activated switch" allows RS232 devices that are normally non-addressable and only usable in point-to-point applications to be added to new or existing RS485 and/or RS422 networks. User programmable settings allow the CAS24 to be used as a versatile tool for constructing networks of almost any size (2-1000+ nodes).

The unit has jumpers for bias, termination, RS232 DTE/DCE selection, mode control, and "external/hardware" unit address (see manual and schematic).The unit has edge mounted LED indicators, a removable screw terminal connector, and SN75LBC184P limited slew rate transceivers (1/2 unit load) with built-in transient protection.

The CAS24 is designed for office and/or industrial applications (non-isolated), and provides superior characteristics/features normally found only on more expensive units. The CAS24 can also be used as a flexible interface converter. A host/remote network can be constructed using only 3 units (One converter and two addressable nodes).

Need something special? Please contact us. We have additional isolated and non-isolated converters, repeaters, and repeater hubs. Units are generally stock to 2-3 business days for shipment. We design and manufacturer our entire product line, and offer technical support for our units, and can offer system recommendations for your application. Please give us a call: 513-874-4796

Related Files:

pdf icon CAS24revC.pdf Converter schematic/physical Rev C
pdf icon CAS24 Manual.pdf Operating Manual (Good information for all CAS units)
CAS24 software icon CAS24.exe Setup Software for CAS24 Windows 95,98,NT

Physical Properties and Features:

RS232: 3-wire interface to RJ11/12 Connector (TX, RX, Common)
RS485: Removable screw terminal (Common, TX/RX-, TX/RX+, RX-, RX+, Common)
Power: 2.1mm center positive "Barrel" connector (9VDC) and Wago terminals
LEDs Power(YEL), TX-RS485(RED), and RX-RS485(GRN), and RS232 enabled(GRN)
Bias: 620 Ohm pull-up and pull-down (jumper selectable)
Termination: 120 Ohm (jumper selectable)or 240 Ohm (jumper selectable)
Special: Switching regulator, Windows software for setup
Protection: Up to 400W typical per SN75LBC184P specification


Distance: RS485 up to 4000 ft. (1250 meters)
Operation: 2-wire half-duplex RS485or 4-wire RS485/RS422
Format: Asynchronous 8-data bits, parity optional
Speed: 2400, 4800, 9600, 14.4K, 19.2K, 28.8K, 38.4K, 57.6K, 115.2Kbps
Temperarure:   0-65C (32-150F) ambient
Humidity: 10-90% non-condensing
Voltage: 8-35VDC
Power: Under 3/4 Watt(typical) + external load
Size: 3.50" X 3.00" X 0.9" (PC Board), with connectors: 3.50" X 3.25"
Mounting: 4-Holes 3.00" X 2.25" (built-in standoffs for #6 hardware)

Options and Ordering Information:

CAS24: $109.00 ea. (Circuit board only)
Enclosure: $10.00 ea. (Medium)
Cable: $7.50 ea. (RS232, 7 ft., Specify DB9F-7 or DB25F-7)   
Supply: $8.50 ea. (12VDC @ 200/300 mA wall power supply)
* CAS24 with all options (DB9F cable/Enclosure/PS): CAS24-B9FSPS @ $135.00 ea. (Qty. 1-9)

Need a different configuration or more information? Give Ron a Call at 513-874-4796 or 513-638-0228(Cell)


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