We use mostly 57's and a few 65's. A typical test setup for our radio loops involves 1-2 65's and 5-10 57's. We erase for one hour for 57's, 1-2 for 65's. We write a number on each chip and have a dated log sheet: one row for each chip, one column per day. We put an X in the box if a chip does not program properly and just rewipe the chip If a chip does not program several times, we put it aside. When we have a few set aside, we put them through several 1 hour erase cycles. Any that do not program after that are junked. We also refrigerate chips before cleaning. COM ports: we use 1 to control a radio loop, one for a loop monitor (though we also have a parallel port version) and one for a logic probe monitor we designed, 8 logic probes controlled by a 57. I also use a modem. We configured two COM ports with standard IRQ's and the third with non-standard IRQ, as discussed earlier. The modem is an internal US Robotics WinModem, the latest X2 technology, 33.6, soon to be upgraded to 33.6 upload, 56 download. It is plug and play, finds its own address/IRQ. Ed Todd