Reiss, Here is a super brief definition of TTL:
<a href=http://zone.ni.com/devzone/nidzgloss.nsf/webmain/D4A5C0CDFB870D518625686A0079445A?OpenDocument&node=DZ59452_US>"Brief Definition of TTL"</a>. For a more involved definition try this link: <a href=http://digital.ni.com/public.nsf/3efedde4322fef19862567740067f3cc/acb4bd7550c4374c86256bfb0067a4bd?OpenDocument>"Definition of a TTL Compatible Signal"</a>. Please post back with any other questions. Craig H. National Instruments
