RS232 Relay Control

Mounts to Any Existing COM Port
Control Relays and Read 0 to 5 Volt Sensors
Control Through RS-232 of Your Computer or Device

RS-232 Still the Best Choice

While RS-232 is not built into some of today's motherboards, there are many applications where RS-232 is still the best choice. Using a simple USB to Serial Adapter allows you to use RS-232 devices with ease. This combination is actually better than using a device with a onboard USB port, because it eliminates most of your EMI problems while maintaining compatibility with today's computers.

Connects to Third Party Devices

RS-232 devices are perhaps versatile and most popular choices because of their ability to adapt to any other communication protocol and devices. For instance, using 3rd party devices, RS-232 relay controllers can be controlled from GSM modems, Ethernet to Serial Adapters, WiFi to Serial Adapters, USB to Serial Adapters, Bluetooth to Serial Adapters, and Wireless Mesh Network to Serial Adapters. RS-232 will continue to adapt to all emerging technologies, as the foundation for all communication technologies has provisions for RS-232 communications. With the DB-9 or direct wire capabilities this controller can connect to third party devices almost any way possible.

Integrates with Crestron

This relay can integrate with Crestron, in fact we have many Crestron customers using our devices. The most important thing you need to know is how to format the data out the serial port of the Crestron device. Our devices work with Hex/Decimal byte values. Crestron systems usually work with Hex values, our devices start with a header byte of 254, followed by a command (ProXR controllers need 254, 108, 1 to activate the first relay). So you need to convert all of these values to Hex for the Crestron system and send the bytes out the port. For a detailed list of all the commands with descriptions see our ProXR Enhanced Command Set.

Mounts as a COM Port

This ProXR series controller connects through an onboard DB-9 connection or a direct wire connection to your computer and requires a 12VDC Power Supply. This ProXR series controller connects to the serial port of your computer and will mount as a COM port on your PC. Once powered up, the controller waits for a command. A command consists of a few bytes of data in numerical format usually between 2 and 6 bytes. Once the command has been received, the controller processes the command, and sends you back ASCII character code 85 to signal the completion of your command.

ZRS Modules

This board is equipped with a ZRS Module. The ZRS communications module adds RS-232 communications to the board. The ZRS module is powered from the serial port of your computer. The board itself will require 12 volts of power and can be hard wired or you can purchase a "wall wart" type Power Supply at checkout.

Three ZRS Modules Available

There are three RS-232 connection options available for this controller.


ZRS-A Wire It Up	ZRS-B Plug It In	ZRS-AB Both!
Choose Your Connector Choose the connection that fits your needs. The ZRS-A connection is recommended for applications where hard wiring directly to the board is needed. ZRS-B has the full 9-Pin DB-9 connector on the board. The ZRS-AB Has the DB-9 connector but is is located off the board for applications where the board may be place inside an enclosure an the RS-232 connector needs to reach to the side of the enclosure. You can choose one of these connection options at checkout.

Sending Commands

Base Station Software is available at no charge to get you up and running fast (more on Base Station below). Once powered up, the controller waits for a ProXR command. A command consists of a few bytes of data in numerical format (ProXR Enhanced Command Set) usually between 2 and 6 bytes. Once the command has been received, the controller processes the command, and sends you back ASCII character code 85 to signal the completion of your command. If a command was sent to read the status of the relay the status is sent back.

Induction Capacitors

Perhaps the most overlooked aspect of relay control is proper handling of inductive loads. Inductive loads can best be defined as anything with a magnetic coil, such as a motor, solenoid, or a transformer. Controlling a inductive load using this relay controller requires the use of induction suppression capacitors. The purpose of this capacitor is to absorb the high voltages generated by inductive loads, blocking them from the contacts of the relay. Without this capacitor, the lifespan of the relay will be greatly reduced. Induction can be so severe that it electrically interferes with the microprocessor logic of our controllers, causing relay banks to shut themselves down unexpectedly. In the case of Serial devices, it is not as severe as using a USB port a capacitor is still recommended. Capacitors that we offer are available at checkout, for more information view our Induction Suppression Video.

USB Induction Solution

If USB is required, a USB to RS-232 adapter (available at checkout) can be used in combination with the RS-232 controller. The USB to RS-232 adapter will allow RS-232 communications between your USB port and this controller with no complications. The RS-232 communications format with a capacitor effectively blocks induction to safe levels for a USB to RS-232 adapter to function without errors.