Operating instructions

CHAPTER 2 TECHNICALLY SPEAKING

Time Domain Reflectometry

NTI also tests long video cables using time domain reflectometry (TDR) to ensure signal quality over long

cables (over 250 feet). TDR measures reflection time to avoid offsets. If the signal reflection is too great, the

signal quality degrades as it travels along the cable. TDR ensures that the signal R, G, and B will be within

¼ pixel of each other.

RS232 Compatibility

NTI KVM switches are RS232 compatible with the addition of an optional module to the switch console.

This configuration is especially good for multiple user applications. This is also a low power consumption

application.

When users connect to the RS232 boards, they get on-screen commands rather than the console buttons. This

is very helpful when the KVM application resides at a remote location; it eliminates the need for the user to

get up and go to the KVM switch console to change to different computer ports or to perform tasks.

The optional RS232 control offers the following features:

 300-9600 baud rate (DIP switch-selectable)

 Up to 15 DIP switch addresses; daisy chain compatible and one serial port control

 Seven-segment display that shows what input is connected to each output

The RS232 commands include:

 RS to reset IN1 to OUT1, IN2 to OUT2, and so forth.

 CS to cause one INx/OUTx connection to occur.

 CA to connect all inputs to specified output.

 RO to read the input that is connected to the specified output.

 RU to read the matrix size and report the inputs/outputs in the specified switch.

KVM Switching Control

The KVM switch technology is similar across manufacturers. As mentioned in earlier sections, the

differences occur primarily in the processor firmware engineering, as well as in the physical design.

Whether the KVM switch is for a single platform, multiple platform, multiple user, cascading or classroom

application, the process is the same:

1) The KVM switch receives input from the keyboard or mouse.

2) The KVM switch translates the input data to the engineered code.

3) The KVM switch translates the data again to the correct output for the particular computer platform.

4) The KVM switch directs the data to the correct port (and user, where applicable).

The method for switching between connected computers depends on the configuration of the KVM switch

you purchase. In its simplest form, the KVM switch console contains buttons that you push to activate

computers. In a more complex form, you can select a variety of different functions from an on-screen display.

Push Button Control

The front of the KVM switch console contains buttons that correlate to each port. Simply push the desired

button to activate the computer connected to that port. The switch sends signals to that computer and

receives output data that appears on the monitor.