Robert de Forest wrote: > I told my boss it's easy to use Linux as an ISDN > modem/router/gateway/firewall. After days of telling him this, he finally > let me go ahead and set it up, and I've been unable to do it.
> I've been trying to setup a USR Courier I-Modem (internal) on a debian 2.0 > machine. I've found many verbose web pages telling me how to get all sorts > of ISDN modems working, but not modems that behave like "normal" modems, > and definitely not USR Couriers. > > Since I can talk directly to the modem with minicom and I can set the > ISDN-specific parameters that way, I figure I don't need an ISDN driver. I > am even able to get a CONNECT 64000 when I tell the thing to dial, but if I > tell pppd to take over it (pppd) gets a SIGHUP eventually. When I manually > dial, I can't detect any data flow, just the connection. > > So here are my actuall questions: > 1) What's the Debian/Linux way to research this kind of problem? Use the diald package, Luke. It provides on-demand dialup, making your network connection transparent. Then all you'll need to do is set up a few simple settings in the /etc/diald/diald.options file and add your auth info into /etc/ppp/pap-secrets or /etc/ppp/chap-secrets and you'll be on your way. I'd be happy to help you get these files set up, email me for examples. > 2) Is my assumption that I can treat this device like a normal modem > correct? If minicom works, then yes. > 3) I noticed while messing with this modem that it seems to handle PPP > onboard. If this is the case, do I need a custom pppd to account for this > (ipppd?), or do I need to turn this feature off, somehow? Nope, you just need to turn on the courier's 'PPP Sync-To-Async' conversion.You see, ISDN is a synchronous data service, which means that there's just a stream of bits which blast through continuously in tune with a clock signal. Asynchronous data, on the other hand, frames each word (read: "byte") sent with start/stop bits and sometimes a parity bit. Since with synchronous serial data you're getting a continuous stream of bits you need to have some way of telling where each piece of data starts and ends. This is accomplished with HDLC framing. Basically, a special pattern of bits starts and ends "frames". The sender makes sure that this sequence of bits is only sent to mark frames (if discovered in regular data, it is "escaped"). Now, your serial port can *only* do asynchronous communication, so in order for you to communicate PPP to the other end (which is usually using synchronous PPP) the modem needs to translate the HDLC packets coming in and provide them to you as PPP HDLC packets. The alternative uses something called V.120 but that probably isn't what your provider uses. So, you need to find out what switch sets your TA to do PPP sync-to-async conversion and you'll be humming right along. > P.S. I'm only subscribed to debian-user-digets, so please CC me in your > responses. Thanks Bad form! 8) -- Jens B. Jorgensen [EMAIL PROTECTED] -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
