At 2009-07-04 17:03, Dave Hachadorian, K6LL, wrote: >I had trouble using optocouplers. They wouldn't key the rig. . . . Dave, A reliable system using optocouplers appeared in: QST, Sept 2004, 28-33. The expanded version, with schematics and details, is available at: http://www.arrl.org/files/qst-binaries/hapirat.zip Best regards, Mark, K5AM www.zianet.com/k5am