Blackmagicdesign Videohub Installation And Operation Manual page 922

Videohub RS-422 Protocol
General
The RS-422 protocol can be used to control many Videohub models as RS-422 slave devices,
for router crosspoint switching. This feature is available on any Videohub model with an
"RS-422 Control" port.
Depending on your model of Videohub, the RS-422 port may be either a DB9 or RJ11 connector.
DB9 cables are commonly available in electrical stores. The RJ11 connector is the same used in
many landline telephone connections. By modifying an RS-422 to USB adapter cable
terminated with an RJ11 connector you can control Videohub using external controllers via USB.
In "Leitch Server" mode, these Videohub models implement the router (server) side of the
Leitch Serial Pass-Through Protocol as specified in section 4 of Leitch document SPR-MAN
revision D. In "Leitch Client" mode, the Videohub implements the controller (client) side of the
Leitch terminal protocol.
5 4 3 2 1
9 8 7 6
Videohub RS-422 Router Control DB9 pin connections.
Videohub RS-422 Router Control RJ11 pinout diagram.
This document describes the commands and parameters in the protocol that are relevant and
supported by Videohub. Other commands and parameters specified in the Leitch protocol are
accepted but ignored.
The RS-422 serial port is configured as 9600 N81.
The protocol is line-oriented, with a maximum length of 250 characters per command. Each
command from the client should be terminated with a carriage-return (\r). Each response from
the server will be terminated with a carriage-return and line-feed (\r\n).
Sources, destinations and levels are always specified in base-16, numbered from zero. Levels
are always between 0 and 15 ("F") . Videohubs only have one valid level - level zero.
Pin Function
1 Ground
2 Tx- (Data sent by router)
3 Rx+ (Data received by router)
4 Ground
5 NC (No connect)
6 Ground
7 Tx+ (Data sent by router)
8 Rx- (Data received by router)
9 Ground
Pin No. Function
Pin 1
TX +
Pin 2
TX -
Pin 3
GND
Pin 4
GND
Pin 5
RX -
Pin 6
RX +
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