Here's the rear of the adapter. The identical set of pins in two rows at each end are the SE power connectors. The row of five pins alongside one edge is the DE-9 connector. The rest of the pins belong to a single black block, per the eBay pic, which seems to plug into the circuit board as a single unit. The only way to get more detail about the upper traces would be to disassemble it. Based on the pin configuration, it appears to contain the equivalent of two ICs and several other items between them. Whatever this actually does it is significantly more involved than a simple TTL adapter.

http://farm4.static.flickr.com/3259/2768848563_e5d2ecdfdb_o.jpg