4x4 Video/Stereo Audio
Vertical Interval Matrix Switcher
OMX-4X4
812 Kings Highway • Saugerties, NY 12477
A Division of Tower Products, Inc.
OMX-4X4 SWITCHER SERIAL PROTOCOL SPECIFICATIONS
1.0
PROTOCOL DEFINITION
The serial protocol used by the OMX-4X4 switcher is an asynchronous byte oriented protocol
at 9600 bits per second, no parity, 1 stop: commonly referred to as 9600, N, 8, 1.
There is no protocol encapsulation (e.g., HDLC,SLIP, etc.). Each valid code sent signifies an
operation of the switcher. The switcher contains an 8 byte receive buffer therefore a program-
mer should be careful no to overflow the buffer, causing received bytes to be dropped. As a
guideline, the host program (MAC or PC) should delay 5 milliseconds between send codes.
Table 1 shows the codes for connecting outputs to inputs for basic switching. Note that audio
follows video.
TABLE 1.0: BASIC SWITCHING CODES
HEX VALUE
DESCRIPTION
0x80
0x90
0xA0
0xB0
0x81
0x91
0xA1
0xB1
0x82
0x92
0xA2
0xB2
0x83
0x93
0xA3
0xB3
Connect output 1 to input 1
Connect output 2 to input 1
Connect output 3 to input 1
Connect output 4 to input 1
Connect output 1 to input 2
Connect output 2 to input 2
Connect output 3 to input 2
Connect output 4 to input 2
Connect output 1 to input 3
Connect output 2 to input 3
Connect output 3 to input 3
Connect output 4 to input 3
Connect output 1 to input 4
Connect output 2 to input 4
Connect output 3 to input 4
Connect output 4 to input 4
