Kramer Electronics Cobra R1300A user manual Problem Solution

Solutions to Common Problems

Problem:	Serial communication doesn’t work correctly.
Solution:	Are the serial devices connected properly? Are the serial
	parameters correct for source/destination devices?
	Are the serial cables terminated correctly? If a null-modem cable
	is used, it must be placed at the receiver end.
	When using RS-232 transmitters or receivers in daisy chains, CAT
	5 switches or CAT 5 distribution amps, the serial signal is a
	unidirectionally broadcast mode only. In this mode, all other
	Cobra CAT 5 Video System devices must be the simplex serial
	type.
	The last device in a transmitter-to receiver or daisy chain
	configuration must be terminated. The R1300A can be used as
	either a “middle unit” or an “end unit”; the termination switch is
	located on the front of the unit.
Problem:	“Green shift” or “green washout” on multimedia signals.
Solution:	The standard video/serial model is designed to function with DC
	coupled signals in which the black level is referenced to 0 volts.
	Nearly all VGA cards function this way. Some media servers,
	however, provide AC coupled signals and can cause a green color
	shift in the video. This is a result of the sync clamping on the red
	and blue channels of the video/serial model. For five-component
	(RGB/H&V) AC coupled video, the Cobra CAT 5 transmitter has
	been designed with full DC restoration capability. This problem is
	easily solved via a simple switch setting in the Cobra Transmitter.
	Refer to the Cobra Transmitter user manual.
Problem:	Notes on Daisy Chaining:
Solution:	When daisy chaining, the maximum cable distance is not
	increased beyond the rated distance of the receiver used. For
	example, the maximum distance from a transmitter to the last
	R1300S2 Receiver in a daisy-chain is 1300 feet. . If a unit in the
	middle of the chain loses power or is disconnected from the chain,
	all units after this will lose signals. All serial communication in a
	daisy chain is one way simplex.

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