The manual for the ErgoTech SECS1/HSMS protocol converter can be downloaded here.

The protocol converter ships with a default IP address of 192.168.5.104 . In order to configure the converter you will need to access the web server in the converter from another computer. One easy way to do this is to directly connect from a computer to the converter using an Ethernet cable. Change the IP address of the computer to be on the same network as the converter so that you can access the web pages. For example, set the IP address of your computer to 192.168.5.101.

If you are using a Windows computer this help page from Microsoft describes how to set your IP address.

Converter Pinout

The male DB9 connector is a “DCE” RS232 device with this pinout.

(Image from WikiMedia)