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LTM-DV4X1
Vertical Interval
IEEE 1394 DV Switcher
Simultaneous Control of an Arbitrary Number of 4x1 Switches
Set the serial port the same way as for the single switch control. Connect the 4x1 switches
using one serial cable and one Daisy-chain adapter cable for each extra unit to be controlled.
Send a series of numbers between 1 and 4 with each number representing the input desired
for each 4x1 switch followed by the CR.The last number sent will control the 4x1 switch that
is electrically nearest the controller in the Daisy-chain connection, the next to last number will
be for the next to nearest switch and so on. For example, if three 4x1 switches,A B and C, are
connected in the following manner; the control cable goes from the controller to an adapter
and to 4x1 switch A. The next serial cable goes from the adapter at switch A to a second
adapter which is connected to 4x1 switch B. Lastly, a third serial cable connects to 4x1 switch
C. Next, the following sequence of characters are sent:
1 2 3 4 CR
After the controller sends CR, 4x1 switches A, B and C will display as output Input 4, 3 and 2
respectively. The 1 number will have been ignored by all switches as only the last three num-
bers are remembered in this setup.
In this control protocol, each 4x1 switch keeps for itself the last number received and passes
on to the next stage the previous number received. The CR is always passed on. In the above
example, the controller will receive:
1 CR
This is a way for the controller to tell that there are three 4x1 switches connected to its seri-
al port as four numbers were sent and one number was returned or echoed.
OPERATION - RS232 CONTROL
