> Some pay phone and CO 2 wire trunks use a momentary ground on one side of > the line to bring up the dial tone once you gave gone off hook. Yes, this is called a 'ground start' rather than the normal 'loop start' Bob Amemrman RAm Systems -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu