Your Matrix Switcher
KRAMER ELECTRONICS, LTD.
4
3.1.7
Port Definitions
Modern equipment usually has only one connector, RS-422, which
functions as a Master as well as a Slave
Some older broadcast equipment contains 3 RS-422 connectors; RS-422-In,
RS-422-Out and RS-422-In/Out. You can only connect a Master to a RS-422-In
port and you can only connect a RS-422-Out port to a Slave. When connecting
to a RS-422-In/Out port
1
the unit changes dynamically, automatically
reconfiguring the DB9 port pins to be either a Master or a Slave
3.1.8
More Than One Slave
Communication between one Master and one Slave is simple. However,
communication between one Master and several Slaves, for example, in
duplication applications, is more complicated
If all the Slaves were to respond simultaneously to a Master command, the
system would grind to a halt. To avoid such a situation, a special algorithm in
the
VS-4216
dictates that the Master will receive only the response from the
highest priority slave
2
with more than one Slave device. For example, in a setup
in which port # 7 is the Master, and ports # 5, # 3 and # 6 are Slaves, the
VS-
4216
will only transmit to the Master the reply from port # 3 and will discard all
the other replies
Pay special attention: in broadcast applications, the most common reply
message from a Slave is the TIMECODE data, therefore, with the above-
described algorithm; the response will come from the lowest numbered Slave
4 Your Matrix Switcher
Figure 3 illustrates the front and rear panels of the
VS-4216
. Tables 1 and 2
define the front and rear panels of the
VS-4216
, respectively.
1 Item 1 in Table 2
2 The lowest numbered Slave device
