Support Document

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IOX-COMSPREAD (Discontinued)

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The IOX-COMSPREAD allows Rexroth® Compu-Spread® CS-440 and CS-550 solid and liquid material controllers to send data through the Geotab® GO™ device to MyGeotab™.

Top Features

  1. Extract data from MyGeotab using the Geotab SDK
  2. Connect to Compu-Spread controller to collect spread amounts and status information
  3. Visit the Substance Spreaders Protocol document for more information.

IOX Hardware Technical Specifications


120 g


Overall Length: 1230 mm L

Widest Point: 19 mm × 31 mm


Black, moisture-resistant thermoplastic overmold


CAN: 500 kbps (for daisy chaining)

COMSPREAD Female: 300 to 115200 baud, parity, data bits and flow control

Power Output

Interface: 900 mA @ 12 V/24 V

Daisy Chaining: 2500 mA @ 12 V/24 V

Current Rating

Operating Mode: 30 mA

Sleeping Mode: 0.2 mA

Temperature Rating

-40 ℃ to +85 ℃


Male Mini-USB Type-B connector: Daisy chain power & CAN in

Female Mini-USB Type-B connector: Daisy chain power & CAN out

Dual Wire: red and black wires for third-party device power. Do NOT use.


Male Mini-USB plug connects to the GO device or another IOX™ harness.

Female DB9 connects to a serial device

Compatible Devices


IOX Installation Instructions

✱ NOTE: Professional Installation Required — Installation of the IOX-COMSPREAD requires the installer to have sufficient technical knowledge and expertise for mobile device installation and integration into modern vehicles, such as a Certified Geotab® Installer certification or equivalent.

! IMPORTANT: The GO device must be disconnected from the vehicle prior to installation. Following installation, you must read and follow Important Safety Information and Limitations of Use for this harness/IOX. Additionally, you must read and follow all Instructions and Warnings to prevent serious injury and/or vehicle damage.

WARNING! Prior to IOX-COMSPREAD installation, read and follow GO device installation instructions ( to verify any existing GO device installation is correct in preparation for IOX-COMSPREAD installation. Incorrect installation of either the GO device, and/or IOX-COMSPREAD can result in loss of vehicle control and serious injury.

WARNING! Prior to IOX-COMSPREAD installation, please read and follow Important Safety Information and Limitations of Use, located at the end of the document. Always read and follow all safety information to prevent loss of vehicle control and serious injury.

How to Install IOX-COMSPREAD


Unplug the Geotab GO device from the vehicle and remove the IOX expansion port cover on the GO device.

Line drawing of GO device (Side view)


Plug in the 90° USB connector from the IOX in to the GO device. Secure the USB connector using a zip tie. Please note that over tightening the zip tie may damage the USB connector.

Note: Insert the USB connector in the orientation displayed in the image.

Line drawing of IOX USB connector being plugged in to GO device


Choose an appropriate mounting location for the Compu-Spread accessory.

Note: The location you choose for the GO device influences the locations available to mount the accessory due to the wire length on the IOX-COMSPREAD. Please ensure the installation does not interfere with safe vehicle operation.


Connect the third-party device to the IOX-COMSPREAD using the female DB9 connector on the IOX-COMSPREAD. Please note that both the Compu-Spread CS-440 and CS-550 can be connected with a male or female DB9 adapter based on the requirements in the Connection Types table below.

Note: The DB9 connector does not provide power to any connected third-party device.


The external red and black wires on the IOX-COMSPREAD are NOT required for supplying power to the COMPUSPREAD device. Do not connect the two wires to the COMPUSPREAD, the vehicle battery/power, or a power source.

WARNING! Connecting the IOX-COMSPREAD red and black wires to vehicle power or any other connection may cause electrical heat/fire damage to the GO device, vehicle and/or serious burn injury.


Once you connect the IOX-COMSPREAD to the GO device, plug in the GO device and immediately start the vehicle. The GO device will enter debug mode.

Line drawing of GO device being installed in asset


Navigate to to verify that the device is communicating.

  1. In the Installer information section, enter the installer’s name and company name. Select the next section.
  2. In the Device serial number section, enter the 12-digit alphanumeric serial number, located on the bottom of the device, then click Validate. Select the next section.
  3. In the Device status section, review the status of the device. The PASS status indicates the device communicated with the network in the last 24 hours. The FAIL status indicates the device has not communicated with the network in the last 24 hours. Select the next section.
  4. In the Vehicle section, enter the vehicle-related information.
  5. NOTE: If the device is not communicating, please ensure the device is installed correctly and try again.

Image of MyInstall user interface

Supported Rexroth Compu-Spread Models and Suggested Adapters

The tables below outline the adapters needed to connect to the Female DB9 connector on the IOX-COMSPREAD. Please note that Geotab does not sell the adapters.

Compu-Spread Model: CS-550*

*Ensure that the AVL option is enabled for the interface connected to the GO device.


Adapter Type

IOX Cable

Female DB9

Pin 2 — Rx

Pin 3 — Tx

DB9 M/M Mini Gender Changer

Female DB9

Pin 2 — Tx

Pin 3 — Rx

Male DB9

Pin 2 — Tx

Pin 3 — Rx

DB9 M/F Mini

Null Modem

Female DB9

Pin 2 — Tx

Pin 3 — Rx

Compu-Spread Model: CS-440


Adapter Type

IOX Cable

Male DB9

Pin 2 — Rx

Pin 3 — Tx


Female DB9

Pin 2 — Tx

Pin 3 — Rx

Female DB9

Pin 2 — Tx

Pin 3 — Rx

DB9 M/M Mini

Null Modem Gender Changer

Female DB9

Pin 2 — Tx

Pin 3 — Rx

Rexroth Compu-Spread Units and Imperial/Metric Units

The GO device reports information from the Compu-Spread models in Metric units. If the Compu-Spread unit is set up to report information in Imperial units, then add the following custom parameter to the GO device for proper operation:


<Parameter Description="REXROTH Imp" Offset="56" Bytes="08"/>


Termination Shunt

The IOX comes with a termination shunt installed in the expansion port. If you plan to install more than one IOX in a daisy chain, you must remove the shunt from each device in the line, with the exception of the last IOX connected. The shunt must remain in the last IOX and secured with a zip tie.

The shunt in the last IOX device ensures the GO device detects and configures the IOX, as effectively as possible.

NOTE: Failure to install the shunt in the last IOX may affect IOX communication. To ensure the IOX communicates, please secure the shunt with a zip tie.

Important Safety Information and Limitations of Use

For the latest version of Limitations of Use, please visit:

WARNING! Do not attempt to install, configure or remove any product from any vehicle while the vehicle is in motion or otherwise in operation. All installation, configuration or removal must be done only in stationary vehicles which are securely parked. Attempting to service units while being operated could result in malfunctions or accidents, leading to death or serious personal injury.

WARNING! All in-vehicle devices and related cabling must be securely fastened and kept clear of all vehicle controls, including gas, brake and clutch pedals. You must inspect devices and cabling on a regular basis to ensure all devices and cabling continue to be securely attached. Loose cabling or devices may impede the use of vehicle controls, resulting in unanticipated acceleration, braking or other loss of vehicle control, which could lead to death or serious personal injury. Improperly fastened in-vehicle devices may detach and impact operators upon sudden acceleration or deceleration, which may cause injury.

WARNING! If at any point after an in-vehicle device is installed a warning light illuminates on the vehicle dash or the vehicle stalls or has a marked drop in performance, shut off the engine, remove the device, and contact your Reseller. Continuing to operate a vehicle with these symptoms can cause loss of vehicle control, and serious injury.

WARNING! Your in-vehicle devices must be kept clear of debris, water and other environmental contaminants. Failure to do so may result in units malfunctioning or short-circuiting that can lead to a fire hazard or vehicle damage or serious injury.

WARNING! Do not attempt to remove the devices from the vehicle in which they are originally installed for installation in another vehicle. Not all vehicles share compatibility, and doing so may result in unexpected interactions with your vehicle, including sudden loss of power or shutdown of the vehicle’s engine while in operation or cause your vehicle to operate poorly or erratically and cause death or serious injury and/or vehicle damage.

NOTICE: This product does not contain any user-serviceable parts. Configuration, servicing, and repairs must only be made by an authorized reseller or installer. Unauthorized servicing of these products will void your product warranty.