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LTM-DV4X1
Vertical Interval
IEEE 1394 DV Switcher
The LTM-DV4X1 can be controlled manually by pressing one of the four pushbutton switches
on the front panel. If a signal is present at the input, the button will light up. If there is no
signal, or the signal is corrupt, then the light will flash and the output will be turned off. The
output will automatically return when the signal has been restored.
In switching between two non-synchronized sources, the phasing or relative timing between
the sources cannot be altered nor can their frequencies or basic frame rates. The LTM-DV4X1
switches between the two sources and automatically adjusts its output frame rate to match
that of the switched input. The consequence of the phasing difference is a variable time delay
between the output and the switched input. The range of time delay is from 0.3 to 1.0 frame.
Closing the contact at the GPI connector will cause the switch to advance the input one count
from 1 to 4 and rolling over back to 1. The equivalent circuit of the input is shown below. The
trailing edge (switching to ground) is detected and the minimum pulse width is 10mS.
Controlling a Single 4x1 Switch
To control the 4x1 switch by RS232 control, set your serial port control to 8 bits data, no par-
ity, 1 stop bit, and 57,600 bps baud rate. Control is achieved by sending an ASCII character
equal to 1 through 4 to select input 1 through 4 respectively followed by an ASCII carriage
return (CR). The CR character will activate the 4x1 switch. If multiple numbers are sent then
followed by CR, then the last number sent before CR will represent the input chosen.
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O
PERATION
- RS232 C
ONTROL
O
PERATION
- GPI C
ONTROL
O
PERATION
- M
ANUAL
C
ONTROL
