Steve Blackmore wrote: > The 120 Ohm are not pull-ups, they are to balance the twisted pair. More specifically to absorb the transmision line energy when it reaches the end of the cable. There is significant energy contained in the inductive/capacitive effect as the transient signal edges flow along a transmission line, and they have to go somewhere when the pulse reaches the end. Think of it like a taut rope when somebody snaps one end of the rope. A wave runs down the rope, and will bounce back off the far end if nothing there absorbs the energy. You don't want electrical waves bouncing off the receiving end and heading back up the cable toward the encoder.
Jon ------------------------------------------------------------------------------ Come build with us! The BlackBerry(R) Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9 - 12, 2009. Register now! http://p.sf.net/sfu/devconference _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
