Can I use your single connector I series TREO version with my mp3 player/laptop etc?
Yes you can! Radio Shack makes a 3/32nd (2.5mm) inch to headphone output adapter that will take the single connector I series version and adapt it to headphone 3.5mm 1/8". this will only adapt music and bypasses the speech portion of the I series. The adapter is Part 274-397 found here:http://www.radioshack.com/product/index.jsp?productId=2062474&cp
Or the same adapter can be found from parts express. click here: http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=090-319