Cisco TelePresence PrecisionHD Camera
D14640.12 Cisco Telepresence PrecisionHD Camera User Guide TC6.2, August 2013.
Copyright © 2010–2013 Cisco Systems, Inc. All rights reserved.
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User Guide
The codec uses 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 1080p4x S2
• PrecisionHD Camera 1080p2.5x
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
generates 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):
In this example there is one host, i.e. the codec (the host is
the unit controlling the camera). The host has the address 0. The four least
significant 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 com-
mands 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
specified:
• 90-6Y-01-FF Message length error
(>14 bytes)
• 90-6Y-02-FF Syntax error
• 90-6Y-03-FF Command buffer 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 buffers 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:
• An Initialize message responds as indicated in the
Table of Commands (this message is 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 first
in the chain. Commands and replies that are longer
than 16 bytes are marked on the following pages.
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
The VISCA™/RS–232 control protocol
Contents
Introduction
The Physical Interface
Connecting the Camera
Appendices
Daisy Chaining
Video Output Format
Appendices
