I make a straight-through RJ-45 Jack to DB-9 Male connect.
Item used:

   Port Server (RJ-45 Jack)
   RJ-45 straight-through cable (plug to plug)
   RJ-45 Jack / DB-9 Male connnector.

This is how I made the connector:

 RJ-45 Plug    DB-9 Male
 ------------ ------------
    1 n/a
    2 blue     6 DSR
    3 orange   7 RTS
    4 black    n/a
    5 red      3 TxD
    6 green    2 RxD
    7 yellow   5 sGnd
    8 brown    8 CTS
    9 white    4 DTR
   10 n/a

This cable connects the digi port with the following devices/connctors:

   Animatics motor/DB-9 female serial port.
	New Port ESP300 Motion Controller/Driver.