I only know it an an "Axis 2490 Serial Server", the only part number I can find is: 0108-003-02
This link may help you source one:
The device itself, is not bigger than an external modem, it has two RS-232 ports on the front, and RS485 and a 10/100 ethernet port on the back, along with the power connector.
It's fairly easy to set up, just plug into the LAN and use the utility that you get on the CD, to assign an IP address ( I usually use my Laptop and a crossover cable to do this), then connect the serial port(s) to the Meridian, the type of cable will probably depend on your Meridian. There is a built in web server, to allow you to configure the device. You can define users, to make it secure and change all the standard Com Port settings (Baud Rate, Data Bits, Flow Control etc.) you also define a TCP/IP port number, so that you can telnet through to the Com Port.
You can also setup users, with passwords so that you can restrict who connects through to the com ports and you can also define which IP addresses can connect, so you can make it quite secure.
I use HyperTerminal to Telnet through to the com port, so there's nothing comlex there.