Teleprint 390

Jim> My 11/45 has a seperate "Paper Tape Advance" output on the Jim> console serial interface, whic is set by writing to a register - Jim> I assume that the Teleprint 390 / ASR33 has either a solenoid Jim> drive or a clutch that allows the tape to advance one character Jim> at a time, under processor control. Bit 0 in the receive control register, right? That's supposed to be the papertape reader "reader run" signal. It isn't used as a one character at a time thing; it is read/write and if set remains set until explicitly cleared. The idea is that the system would accept interactive input by leaving this bit clear, but then when you told it to read a papertape it would set the bit. That starts the tape. The program would then see characters streaming in. At some point (perhaps when it sees a string of nulls, or when it knows the tape is finished by some internal coding) it would clear reader run again. I don't know if this actually was used much. The ASR33s I remember rarely if ever had this hooked up; the reader run control was done by flipping the papertape reader switch on the machine. I tried to find some code for it, but RSTS dropped the code in V9.6 and that's the oldest I have... paul