Are any of the DECUS 12 bit SIG newsletters online? I just found parts of two of them in my attic (#39 - March 1980 and #40 - Summer-Fall-Winter 1980) and they have some interesting comments about TU-58s and 12-bit machines. It's interesting considering the recent activity regarding TU-58s and emulators. According to (I think) Jim Van Zee, formerly of Laboratory Data Systems of Seattle), being able to send a break is critical for reliable operation of a TU-58 (and gives the exact reasons). The M707 and the M8650 cannot do this without modifications (but he does describe the mod to the M707 and says that it can be done to the KL8E (M8650) but not the KL8EJ (M8655) or KL8A). The author goes on to describe a handler he wrote for OS/8 - a non- system handler. It adds "DTU0" and "DTU1" of 682 OS/8 blocks. He also writes that it is impossible to write a system handler without an external circuit or ROM code (a-la 8K TD8E + ROM) to calculate checksums. His hardware solution is 4 chips grafted onto an M8650 (one of which is an Intel 8748 microcontroller!) Additionally, he mentions a virtual TU-58 server written for the VAX by Jim Gladden, and describes a submission to DECUS of a non-TU58 serial line device handler for the VAX (ASCII files only) that *may* be submission number 8-921 (my handwritten notes in the margin). So... if anyone wants to hang a TU-58 (physical or virtual) off of a PDP-8, we have somewhere to start. -ethan