Lenovo ThinkCentre A70z Dual monitors?

The Lenovo ThinkCentre A70z is a all in on pc, and on the back there are two ports on is a DB9, a 9 pin vga in a way, and the other is something that i've never seen before. I'm trying to hook up another monitor so i bought a DB9 to HD 15 converter and hooked it up to my other monitor, but it didn't work. Any help?

These are the ports on your all-in-one:

6 USB 2.0 connectors (3 on the rear panel and 3 on the side panel)
Ethernet (RJ-45) connector
One standard eSATA connector
Two audio connectors (microphone in and audio out) on the side panel
Two PS/2 for keyboard and mice
http://support.lenovo.com/...MIGR-75470

The eSATA is the one you have not seen before.
For more monitors, these are some choices:
A USB to DVI (or HDMI or VGA) external video adapter and its software.
A USB monitor and its software.
Another computer's monitor through LAN by ethernet or wireless and MaxiVistA or ZoneScreen software on both.
If you have a DB9 connector with male pins, this says it is a serial port for in/out of data, not any type of video port. "The back of the unit is clean and organized, below the kickstand there are three more USB ports, the Ethernet port, and a serial port. While serial ports are rare on consumer desktops, they still may be needed on business desktops for older peripherals like magnetic card readers and bar code scanners." http://www.pcmag.com/...539,00.asp