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Cisco TelePresence PrecisionHD Camera PrecisionHD Camera User guide
D14640.09 PrecisionHD 1080p-720p Camera User Guide, June 2012.
© 2010-2012 Cisco Systems, Inc. All rights reserved.
www.cisco.com
The VISCA™/RS–232
control protocol
The codec is using the Sony Visa protocol to
control the cameras.
Interfacing the camera
When interfacing to the camera the codec
uses an RS-232 control interface that
resembles the Sony VISCA™ protocol.
Supported cameras
The following Cisco PrecisionHD cameras are
supported:
• PrecisionHD 1080p12x
• PrecisionHD 1080p4x
• PrecisionHD 1080p4xS2
Currently there is support for detection of the
following third party cameras:
• Sony HD1
• Sony HD7
VISCA message format
A particular command is recognized by the
message information after the address byte.
Message Format
Commands are initiated from the host (i.e. the
codec or any other external controller) to the
camera.
After a camera has been issued a command,
the camera will generate a response.
Commands and responses (messages) have
the following format:
• Address byte (1)
• Message bytes (1..14)
• Terminator byte (1)
See the illustration for details.
The minimum length of any command or response is 3 bytes:
1. Address byte (1): Let us assume there is one host, i.e. the codec (the host is the unit
controlling the camera). The host has address 0. The four least signicant bits of the address
byte contain the address of the receiver. In the case of a broadcast message, the receiver
address must be set to 8. When we are operating a single camera, the address is 1. Hence,
address bytes in messages from the host are 0x81, and messages from the camera to the
host are 0x90 (the protocol allows for up to 7 cameras).
2. Message bytes (1..14): Any number of bytes containing the actual message information. Bytes
may have any value in the range 0...254. The value 255 (i.e. hexadecimal FF) is reserved for
the terminating byte.
3. Terminator byte (1): All messages must be terminated with a byte containing all 1’s, i.e.
decimal 255 (or hexadecimal FF).
Command and response exchange
When the camera receives a command, it
responds with either:
• Completion message: 90-5Y-FF
Returned by camera when execution of
commands and inquiries are completed.
• Error packets: 90-6Y-..-FF
Returned by camera instead of a
completion message when command or
inquiry failed to be executed.
• General error messages, unless otherwise
specied:
• 90-6Y-01-FF Message length error
(>14 by tes)
• 90-6Y-02-FF Syntax error
• 90-6Y-03-FF Command buer full
• 90-6Y-04-FF Command cancelled
• 90-6Y-05-FF No socket (to be
cancelled)
• 90-6Y-41-FF Command not executable
• Y = socket number
A camera may contain two buers so that
two commands, including the command
being executed, can be received.
NOTE: The PrecisionHD 1080p
camera supports a single socket only.
Consequently, the Y always assumes the
value Y = 0.
Exceptions to these rules:
• An Initialize message will respond as
indicated in the Table of Commands (this
message is in fact a broadcast message,
and any unit other than the host receiving
the broadcast message must pass it on).
• Do not route commands or replies that
are longer than 16 bytes through Sony
cameras. The easiest way to avoid this is
to put the Cisco cameras rst in the chain.
Commands and replies that are longer than
16 bytes are clearly marked below.
The RS232 Message format
...
Sender’s
address
Receiver’s
address
1 0
LSB
Packet (3 to 16 bytes)
Message (1 to 14 bytes)Address
Byte 1 Byte 2 Byte 3
Terminator
FF
1 1 1 1 1 1 1 1
LSB
Contents
Appendices
Introduction
The physical interface
Connecting the camera
Video output formats
Daisy chaning
Appendices