AJA Ki Pro Ultra Machine Control Manual page 6

Chapter 1 – Introduction
1.0 Overview
This document describes aspects of the machine control protocol processing for
Ki Pro Ultra 12G, Ki Pro Ultra Plus, and Ki Pro Ultra digital video recorder/players.
It is intended for engineers, either software or hardware, who are interested in
controlling Ki Pro hardware via its RS-422 interface.
The guiding document for this protocol is the Sony Video Cassette Recorder/
Player, Protocol of Remote (9-pin) Connector, 2nd Edition (Revised 11), and more
specifically the SRW-5500 information presented in that document.
Aside from introductory information, this AJA document includes only the
command and status information supported by AJA's Ki Pro Ultra and Ki Pro Ultra
Plus recorder/players.
Some of the commands and status bits described are actually emulated, to allow
a device controller to communicate with a Ki Pro as if it were a VTR, instead of a
disk recorder. These commands and statuses may not indicate an actual change
of the Ki Pro's operational state, because the underlying Ki Pro hardware does not
provide that functionality.
In this document the definitions of CONTROLLER and DEVICE are:
• "CONTROLLER" indicates the unit that controls a device.
• "DEVICE" indicates the device (Ki Pro) that is controlled by a unit.
1. 1 Interface System Overview
• Conforming to EIA RS-422A.
• Full duplex communications channel is utilized.
• Data is transmitted asynchronously, bit serial, word serial with data exchange
between devices.
• Standard transmission rate on the interface bus is 38.4 kilobits per second
(kbps).
• The data word utilized by the interface system is as follows:
Figure 1. Data Word
• 1 START BIT + 8 DATA BITs + 1 PARITY BIT + 1 STOP BIT. ODD parity : The total
of "1"s in D0+D1+ . . . D7+PARITY equals an odd number.
1.2 Command Block Format (CMD BLOCK)
The communication between the CONTROLLER and the DEVICE is composed of
CMD-1 + DATA COUNT, CMD-2 + DATA and CHECKSUM, and is transmitted from
CMD-1 + DATA COUNT in order.
When DATA COUNT is zero, the data is not transmitted.
When it is not zero, the data corresponding to the value is inserted between
CMD-2 and CHECKSUM.
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