Date: Sat, 21 Jun 1997 14:27:21 -0700 (MST) From: Terry Lambert <terry@lambert.org> To: adam@veda.is (Adam David) Cc: terry@lambert.org, freebsd-current@FreeBSD.ORG Subject: Re: getty modem control Message-ID: <199706212127.OAA27870@phaeton.artisoft.com> In-Reply-To: <199706210043.AAA17361@veda.is> from "Adam David" at Jun 21, 97 00:43:55 am
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> > > I'm not making any progress with using the modem init string capability. > > > (DTR lights up but there is no flicker on TXD) > > > > Look at the CTS/RTS settings, and how they effect the modem and > > UART in the DCD-not-present state, in particular. > > Are you saying I need a special cable because the software is a hack, > or am I misconfiguring the software? No. I'm saying that CTS/RTS may be active, even in the absence of DCD. If so, this modem is either broken, or misconfigured. Typically, command interchange with a modem does not involve data exchanges larger than the buffer size. The CTS/RTS should not be required until DCD is high, and thus the modem is doing data, not command, interchange. Typically, the symptoms are "no data back from modem until DCD is present". If you can't change the modem settings, then you will be limited to blind-dialing in all cases. > > You make a "modem driver" and seperate "inbound" vs. "outbound" > > tty device operations. The main problem is that most of these > > damn "do everything" getty programs like to initialize the modems > > to a state which is optimal for them. This is the same reason > > you can't share amodem between an intermittent ISP connection and > > a FAX server on most Microsoft platforms. > > If there is a modem driver, getty does not have to meddle with the modem > at all, correct? If there is a modem driver, getty is *PROHIBITED* from meddling with the modem at all. If it talks to the modem, it is committing a crime. > > The RI stuff is a hack I suggested > > to use as an inbound call marker; as you've discovered with 9 pin > > ports, it's not a very good hack. 8-(. Better to support inbound > > call fanning to voice/data/fax devices as seperate entities. > > There is no other marker of calls inbound. CD signals an established call. > RI is much simpler to implement as an external circuit than CID, but if > the serial port is broken by design then you take your chances. Actually, if you have a driver, then you are permitted to receive data befree DCD is asserted. The tty is not permitted to open until DCD is asserted in the data-call-answer case. The driver would "fan out" inbound calls to a voice device, a fax device, and an inbound tty. There may be a sperate DTMF device, but more likely it will be piggybacked on the voice device. A driver-based soloution could use data from the modem with DCD low as marker data, and interpret it as "cachable caller ID" or "soft ring notification", etc.. > > There is actually one modem that creates two serial pseudo devices > > under Windows95/NT: that's the Intel modem for telephony (I can't > > tell you the model without going to the usability lab down the > > hall, sorry). I *really* liked the modem, but obviously, it required > > a per-modem driver to do its thing. It supported Caller-ID as well, > > as a device ioctl (and supported providing your own calling-ID, too). > > Does this or any other readily available/affordable modem handle > full duplex (simultaneous realtime) voice to data conversion that > would be usable for an internet phone gateway? I believe the Intel modem uses a full duplex, ADAC, yes. I'm not real sure about the software controls embedded on the board as far as data directing, etc.. It's a PCI card, if that will help you narrow it down. I've used it for "voice response" -- rather nice, you tell it the name of the person you are calling, and it switches the call to that extension -- more hardware was present for the switching, before you rush out to buy the modem thinking it can do this by itself. The modem, one per inbound line, combined with a dialogic card, is enough to make a machine into a little PBX. 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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