naftoli@aecom.UUCP (Robert N. Berlinger) (09/02/86)
Is it true that DTR will only go high if the communications program
tells it to? Does Red Ryder do this? I am interested, because I want
to be able to set up a Mac+ for *dialin* purposes, and I don't want the
modem to answer unless the Mac is on and ready to talk.
--
Robert Berlinger
Systems Analyst
Albert Einstein College of Medicine
UUCP: ...{philabs,cucard,pegasus,ihnp4,rocky2}!aecom!naftoli
Compuserve: 73047,741brian@ut-sally.UUCP (Brian H. Powell) (09/08/86)
In article <458@aecom.UUCP>, naftoli@aecom.UUCP (Robert N. Berlinger) writes: > Is it true that DTR will only go high if the communications program > tells it to? From IM Volume IV: "The Data Terminal Ready (DTR) line in the RS232 interface is now automatically asserted when the Serial Driver is opened; DTR is negated when it is closed." (They're talking about the new SERD resources == 128K ROM version.) There are also _Control calls to assert and negate DTR: (Issue them to the output channel driver.) csCode = 17 This call asserts DTR. csCode = 18 This call negates DTR. ----- Brian H. Powell UUCP: {ihnp4,seismo,ctvax}!ut-sally!brian ARPA: brian@sally.UTEXAS.EDU
curry@nsc.UUCP (Ray Curry) (09/12/86)
According to schematics I have for the 512 Mac, the dtr pin on the scc is not connected at all. The pin 6 of the connector is permanently tied to +12 volts. I hear Apple had trouble hooking in their telephone system with built in modems because dtr was permanently held high. Perhaps newer macs have changed this but I have never had my modem hang up even when exiting macterminal and returning. I have been tempted to try opening the mac and connecting the dtr up, but since the scc has to be initialized to use the dtr pin, it would impact any software not doing so, so I haven't. Has anybody every confirmed with a breakout box that the dtr signal ever moves? Perhaps rts/cts are being used and refered to as dtr.
jimb@amdcad.UUCP (Jim Budler) (09/12/86)
In article <3773@nsc.UUCP> curry@nsc.UUCP (Ray Curry) writes: +--------------- | According to schematics I have for the 512 Mac, the dtr pin on the scc is | not connected at all. The pin 6 of the connector is permanently tied to | +12 volts. I hear Apple had trouble hooking in their telephone system | with built in modems because dtr was permanently held high. | Perhaps newer macs have changed this but I have never had my modem hang | up even when exiting macterminal and returning. I have been tempted to | try opening the mac and connecting the dtr up, but since the scc has to | be initialized to use the dtr pin, it would impact any software not doing | so, so I haven't. Has anybody every confirmed with a breakout box that | the dtr signal ever moves? Perhaps rts/cts are being used and refered to | as dtr. +--------------- Ah Ha, so that explains it. I've been hearing all this talk about MacTerminal cycling DTR with the new ROMS, and it never happens to me. Well I have the New ROMS, in an upgraded 512. I suspect that the Mac+ has been redesigned slightly to use the DTR. If you have the new ROMS, you may be able to rewire it as described and have it work, since the New ROMS do cycle the DTR (per IM vol IV). -- Jim Budler Advanced Micro Devices, Inc. (408) 749-5806 Usenet: {ucbvax,decwrl,ihnp4,allegra,intelca}!amdcad!jimb Compuserve: 72415,1200 I got tired of my old signature.
mlr0@bunny.UUCP (Martin Resnick) (09/19/86)
> Is it true that DTR will only go high if the communications program > tells it to? Does Red Ryder do this? I am interested, because I want > to be able to set up a Mac+ for *dialin* purposes, and I don't want the > modem to answer unless the Mac is on and ready to talk. > -- Opening the serial driver on the Mac+ automatically asserts DTR. Closing the driver releases DTR. There are also individual commands to assert/release DTR.