Actually - all are right in all regards... What I was trying to say is that yes, you can use it - but it would be a waste, given the speed of a serial port, even with an updated UART. We have it here, but we use it to attach to our network. Once on the net, we can get to one of the 3000's and take full advantage of the speed ISDN offers. Also - be aware - ISDN here in Bell Atlantic country might not be exactly the same as ISDN out there in PacBell country (which is why I always carry around my little Megahertz XJack with me wherever I go <g>)...I have ISDN from the house, which let's me 'telecommute' (and surf :) at nice speeds - but from HPWorld last week - I slogged along at 28.8. <now 'scuse me while I duck while you all throw tomatoes at me or something> Anyway - yes, you can use ISDN with an HP3000, but it's a waste. Use ISDN with your NETWORK (via Windows NT Server and RAS, for instance, or a Shiva - or other server hardware/software), and take advantage of the speed. Hope this clarifies :) Joe