On Wed, 15 Dec 2010, Rogelio Perea wrote: > Jameco (www.jameco.com) still lists the 6551 at about US$4.00 a pop; > granted: it is the 1MHz rated ACIA... but perhaps all that's needed for a > given CoCo project. I was able to get reliable 2Mhz. operation with the Jameco part. YMMV. --