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To achieve maximum range, keep objects such as your hand away

from the antennas and ensure that the antennas on the boards have

an unobstructed line-of-sight path to each other. Range performance is

determined by many interdependent factors. If the range you are able to

achieve is significantly less than specified by Linx for the products you are

testing, then there is likely a problem with either the board or the ambient

RF environment in which the board is operating. First, check the battery,

switch positions, TX output power setting and antenna connection.

Check the range performance on different channels. Next, measure the

receiver’s RSSI voltage with the transmitter turned off to determine if

ambient interference is present. If this fails to resolve the issue, please

contact Linx technical support.

The PC Control Area

The PC Control Area is used with a daughter board to connect the

module’s Command Data Interface to a PC. This advanced feature is a

serial data interface for configuration and data transfer. One USB interface

board is included with the development kit. Additional USB interface boards

or an RS-232 interface board can be purchased separately.

The top DIP switch (1) controls the TRPT/PKT line on the module. This

line selects between transparent data transmission and packet data

transmission. Slide it to the left for transparent data and to the right for

packet data.

The bottom DIP switch (1) controls the CMD_DATA_BAUD line on

the module. This is the data rate for the CDI and has no effect on the

over-the-air data rate. Slide to the left for 57,600bps and to the right for

9,600bps.

8

The Range Test Area

The board features an MT Series remote control transcoder with two push

buttons, a buzzer and an LED. The two boards in the kit are populated

differently so that the button inputs on one board are outputs on the other

board. Figure 9 shows the differences.

When a button is pressed on one board, the status of both buttons is

captured, encoded into a data stream, and transmitted. The data

recovered by the receiving board is decoded and the transcoder’s data

lines are set to replicate the states of the buttons, driving either the buzzer

or the LED. A confirmation packet is then sent to the transmitting board

activating the Confirm LED.

To activate this area of the board, the module’s DATA and T/R_SEL lines

must be routed to the transcoder. This is accomplished by setting the

Mode Select switch to the right position and the Evaluation Select switch to

the middle position.

After the boards have been configured, place Board A on a flat surface

and turn it on. Turn on Board B and press button S1. The buzzer on Board

A will sound and the Confirm LED on Board B will light up. The usable

range of the link in your environment can be ascertained by carrying Board

B away from Board A. Switch SW11 has been provided to continuously

transmit the LED activation without having to hold down a button.

As you near the maximum range of the link in your area, it is common for

the signal to cut in and out as you move. This is normal and can result from

other interfering sources or fluctuating signal levels due to multipath effects.

The areas in which this occurs are commonly called “nulls” and simply

walking a little farther will often restore the signal.

Figure 9: The Development Board Range Test Section

Board A

Board B

9

Figure 10: PC Interface Boards

1

2

3

4

1

3

4

2