58 lines
2.9 KiB
Plaintext
58 lines
2.9 KiB
Plaintext
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CTTY.DOC
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I asked around about the DOS 2.0/2.1 function CTTY and could
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not find anyone familiar with it. So I put on my hacker's cap
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and "went to it." (After midnight, in true hacking style.)
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The DOS manual explains that the command is simply CTTY
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device-name. This will transfer control from the keyboard and
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screen to that device. It suggests that LPT1: is not a good
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idea since the printer communicates (mostly) one way. What
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this really leaves is COM1:, COM2: and AUX: (Whatever AUX:
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is! [I'd love to hear from someone about AUX:])
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I very cleverly tried typing CTTY COM1: It does do something,
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it kills the keyboard and a cold BOOT is necessary to
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restart. Well, that wasn't it. Something must occur prior to
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the CTTY command. Being strictly a seat-of-the-pants type, I
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set the HAYES to ANSWER and called in. Nice, I had a
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connection (CARRIER/carrier). I rushed over to the PC
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keyboard and typed CTTY COM1: and the screen went dead. So,
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what else is new....but, on my other SYSTEM, (other end of
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the office), the prompt A> appeared. I sat and typed on the
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terminal just as though I was sitting in front of the IBM.
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Well, what do you know?
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1) Commands are limited to what the terminal keyboard can
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reproduce i.e. ^C for CTRL-BREAK but not CTRL-ALT-DEL (as if
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you would want that one anyway).
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2) Going to BASIC cuts you off. SYSTEM control returns to the
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keyboard.
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3) Most commands work except COPY as it relates to CON: or
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COM1: COPY from disk to disk worked O.K.
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4) This means is total control from outside while in DOS only
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on a line-by-line basis. Anything which relies on screen
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mapping will not work. (I ran Norton's DISKMAP from the
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terminal and the map appeared on the PC screen.)
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Now...
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You may be wondering why all this verbage. Well.... the
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result of my efforts is a BASIC program called RING.BAS which
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will set up the HAYES to patiently look for an incoming ring,
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and very politely turn SYSTEM control over to the caller. Oh,
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I forgot to mention the BASIC program must be called from a
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BATCH file called OUTSIDER.BAT. When RING goes back to the
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SYSTEM, the next command is CTTY COM1: Slick, huh? RING will
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even write the BATCH file for you. Just take a look at the
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internal documentation for additional information. The
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program is not fancy and I can think of lots to add to it,
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but I am sure you can too.....
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Dan Derrick 2/21/84 70215,1136
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END OF TRANSFER - PRESS ENTER TO RETURN TO MENU
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