Advanced Tubular Loopback Tester Software
From ATTWiki
The Loopback Tester software is designed to allow you to test an RS-232 connection using a loopback connector.
A loopback tester is used to test an COM port cable and connectors with a single computer. The loopback tester is also used to test Benderlink Ethernet Modules. Here are a few images showing various states of the Loopback Tester software in action.