Anthony, the plug you talk about is got that tab that is offset to one side.  It plugs into a small rectangular box that plugs into the serial connector on the computer.  I don't have any idea as to price, but I seem to recall GW Micro have them.  

Good luck and 73,

Paul  WR1X
  ----- Original Message ----- 
  Hi Everyone;

  I have a DECTALK EXPRESS.

  I thought the cord used an rj11 to plug into the express and the computer 
  however, the pin for this plug is off center.

  Can anyone tell me what this plug is and if I can get a longer cord for it 
  without paying some enormous amount of money for something proprietary?

  Thanks

  Anthony