Date: Thu, 11 Jul 1996 23:12:57 -0700 (MST) From: Terry Lambert <terry@lambert.org> To: tcg@ime.net Cc: terry@lambert.org, martin.loeffler@utoronto.ca, questions@freebsd.org Subject: Re: forcing a modem to hangup Message-ID: <199607120612.XAA00740@phaeton.artisoft.com> In-Reply-To: <31E5C356.745E@ime.net> from "Gary Chrysler" at Jul 11, 96 11:15:34 pm
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> > Well, don't buy bad internal modems. 8-|. > > > > The problem is that you can't issue a blanket rule that way when > > manufacturers don't put "bad modem" on the outside of the box, > > since "the dealer told me it was a good modem, and you didn't > > give me a list of good modems, so I bought it". > > > > Huh, What? > > You get what you buy, Internal or External! > Buy from K-Mart you deserve what you get. Gary: Can you name an internal modem which does not float open collector the RTS between the modem UART and the modem chip? That can be powercycled without power-cycling the machine? That doesn't use a Rockewll chipset, since some of the people I talk to has US Robotics 14.4 Courier/Faxmodems with the firmware bug? That itself is not a US Robotics Courier because some of the people I talk to have Rockwell chipsets? That doesn't trigger the delay requirements in the SIO driver comments because it emulates a UART instead of having one? That has a FIFO'ed UART? That if it gets fried, can't fry my machine, because like my serial ports, it includes optoisolators? That internally does not float DTR open collector so it won't answer the phone unless I set the DTR flag? And that, by default, following POST, can be programmmed to have a default DTR flag unset, so that the modem will not answer the phone until my system is up so that the number will roll over like its supposed to in case of system failure? It's possible to make a pretty long list of external modems which do this, mostly because RS232C interfaceing and serial PORT post conditions are well known. Fake RS232C "UART->modem" internal wiring is more suspect. A can only think of one modem that meets these requirements, and I can tell you, they want my left testicle for it ($445). When things need to work, they *need* to *work*. It's possible to get working internal modems; as a general rule of thumb, however, external beats internal for quality, if only because RS232C does not allow pins 4,5,6,8,and 20 to float open collector; they are defined as being pulled down in the absence of a definite state setting. The POST leaving the DTR off in any decent BIOS without a specific UART setting to enable it is just icing on the cake. Regards, Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.
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