The pin out in this image shows the RJ45 female and DB9 female numbers.
DB9 female to RJ45 male
DB9 female to RJ45 female
In order to check the communication between de computer and the Tech2 the first thing to check is the RS-232 functionality on the Tech2 device. The Tech2 uses the RJ45 connector for the RS-232 serial out. The RS-232 functionality can be checked by using a special RJ45/RS-232 loop back plug.
First make sure that the serial Loopback is working.
As the loop back functionality has passed then move to the next link in the chain. USB to serial converter
First figure out which COM port the Tech2 is connected to.
Download the PuTTY program which allows you to eavesdrop on the Tech2 device.