Ic-net control protocol, Overview, Command string structure – Contemporary Research ICC2-ATSC User Manual

Page 15

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Contemporary

Research 15

ICC2-ATSC HDTV Tuner/Controller

IC-Net Control Protocol

Overview

RS-232 control for up to 4000 TV Controllers is provided through an iC-series Head-End Network

Controller. The ICE-HE Ethernet Head End and ICC-HE Head End manage iC-Net communication

over RF Coax to ICC1 (1-way) and ICC2 (2-Way) TV Controllers.
Each TV Controller is assigned a unique device number from 1 to 4000 to which control

commands are addressed. The devices are organized into 16 zones of 255 devices. All the devices

in each zone will respond to a single “virtual device number” — one device number that

represents all devices in each zone. There is also a global device number, 4095, that will

command all devices in the system. This feature dramatically speeds up system operation and

programming, because one command can affect an entire group of devices—or all. To take

advantages of this feature, review the section iC-Net SmartZones in this manual.
In ABC-Net, we reserve the first group of devices, 1-255, for components operating on a

connected control system. Zones 1-16 are used for CR TV Controllers, Video Display Controllers

and Tuners. As it’s unlikely any system will use all 4000 devices, this may be a good device

standard for your system as well.
The Remote RS-232 port on the Head-End Network Controller can communicate from 1200 to

38.4K baud. The factory default setting is 19.2K baud, 8 data bits, No parity, and 1 stop bit.

Command String Structure

Characters in command strings are expressed in a combination of hex and ASCII characters. For

clarity, the following protocol examples use the following conventions:

• Single-byte hex numbers are preceded by the ‘$’ symbol

• ASCII characters or strings are enclosed in single quotes

• Numbers not marked as hex or ASCII are a single decimal byte

• Parameters shown in < > brackets are single byte

• A series of multiple commands or parameters are set apart by [ ] brackets

• Commas separate the bytes, but are not part of the protocol

• Double quotes enclose the command string, but are not part of the protocol

Command format:

“$A5,<dh>,<dl>,<ncb>,<cmd1>,<parameter> [<cmdN>]"

$A5

Starts the command

<dh>

The zone or high order byte of the device*

<dl>

The unit or low order byte of the device (0 for global zone)

<ncb>

The number of command bytes to follow

<cmd1>

The first command byte

<parameter> Command parameters (not used by all commands)

[<cmdN>]

Multiple commands can be concatenated, with byte count added to <ncb>

*

iC-Net devices are arranged with a zone mindset. For example, a command sent to Device 256, which

triggers all the units in Zone 1, would be expressed as $A5, 1, 0 (first zone, device zero). A command sent

to 257 would be $A5, 1, 1 (first zone, device 1 in the zone). See iC-Net SmartZones toward the end of this

manual.

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