Intelligent Roadway Information System
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A controller is an end-point for a comm link. Each controller can have one or more associated devices, depending on the protocol. Sometimes a controller represents a separate physical box, which is connected to devices, and other times the controller may be embedded within the device. In either case, a controller is required for any communication to a device. Controllers can be assigned to a cabinet, which has location information to allow displaying on a map.
Some protocols support multi-drop addressing, while others are single-drop only. Multi-drop addressing allows multiple controllers to share the same comm link — typically for serial communication. Each controller must be assigned a unique (to the comm link) drop address, which is used to route all messages sent to the controller. For single-drop protocols, the drop address is ignored.
Authentication is supported or required by some communication protocols. The controller password field is used to enter authentication data.
- For NTCIP, this represents the SNMP community name. If no controller
password is set, the
Publiccommunity name will be used.
- Web-based devices may require HTTP Basic Authentication. For these types of
devices, the password field should contain both the user name and password,
separated by a colon (
- For CBW, the user name portion must be
none. HTTP Basic Authentication can be enabled on the setup page of the CBW device (setup.html).
- SierraGX modems can be configured to require authentiation. In this case, separate the username and password with a colon, in the same manner as HTTP basic authentication.
A device is one of several types of traffic control or sensing systems. These include:
- dynamic message signs — DMS
- gate arms
- lane-use control signs — LCS
- ramp meters
- road weather information systems
- tag readers
- vehicle detection systems
- video monitors
The controller must also be associated with a comm link which communicates using an appropriate protocol for the device.