–

–

–

–

8

9

Using the Programming Dock

Snap a Carrier Board onto the socket on the Programming Dock as shown

in Figure 9.

Connect a micro USB cable into the connector at the top of the board.

Plug the other end into a PC. The board is powered by the USB bus.

The demonstration software included with the kit or custom application

software can be used to configure the module through its Command

Data Interface. The LCD is used to display information about the module.

This includes the module’s local address and a custom nickname. The

nickname is entered using the development kit software and can be

any name that helps distinguish the modules from one another. This is

convenient when multiple programming docks are connected to the same

computer. Please see the development kit software section for more

information on the nicknames.

is used to configure and control the transceiver. This interface consists of a

standard UART with a serial command set.

Figure 9: Programming Dock with a Carrier Board

Range Testing

Several complex mathematical models exist for determining path loss in

many environments. These models vary as the transmitter and receiver are

moved from indoor operation to outdoor operation. Although these models

can provide an estimation of range performance in the field, the most

reliable method is to simply perform range tests using the modules in the

intended operational environment.

Range testing can be performed with the Programming Docks and / or

the Prototype Boards. Data can be sent across the link using the included

software or a custom microcontroller connected to the module. The RSSI is

included with the output data messages, so this can be used to qualify the

link.

As the maximum range of the link in the test area is approached, it is not

uncommon for the signal to cut in and out as the radio moves. This is

normal and can result from other interfering sources or fluctuating signal

levels due to multipath effects. This results in cancellation of the transmitted

signal as direct and reflected signals arrive at the receiver at differing times

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

and simply walking a little farther usually restores the signal. If the signal is

not restored, then the maximum range of the link has been reached.

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

the antenna and ensure that the antenna on the transmitter has a clear and

unobstructed line-of-sight path to the receiver board. 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, and antenna connection. Next, check the ambient RSSI

value with the transmitter turned off to determine if ambient interference

is present. High RSSI readings while the transmitter off indicate there is

interference. If this fails to resolve the issue, please contact Linx technical

support.