Cisco TelePresence PrecisionHD Camera
D14640.17 Cisco Telepresence PrecisionHD Camera Guide APRIL 2017
Copyright © 2017 Cisco Systems, Inc. All rights reserved.
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Camera 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 Camera 1080p12x
• PrecisionHD Camera 1080p4x
• Precision 40 Camera*
• PrecisionHD Camera 1080p2.5x
Currently there is support for detection of the follow-
ing 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.
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
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
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.
...
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
VISCA™/RS–232 control protocol
*Formerly PrecisionHD Camera 1080p4x S2
Contents
Introduction
Physical interface
Connecting the camera
Appendices
Daisy chaining
Video output format
Appendices
