Date: 7 Apr 1996 15:47:24 -0700 From: jhenders@wimsey.com (John Henders) To: freebsd-questions@freefall.freebsd.org Subject: Re: ISDN TAs Message-ID: <4k9gls$a35@vanbc.wimsey.com> References: <199604070908.BAA03089@MediaCity.com>
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In <199604070908.BAA03089@MediaCity.com> brian@MediaCity.com (Brian) writes: >Dave Andersen wrote: >> I've noticed a fair amount of complaining about the BitSurfrs lately, >> and I'm wondering what people feel overall is the best coice for an ISDN >> adapter, preferably external, for use under FreeBSD. This would be for >> "home office" use >When you talk async over a serial port to an ISDN TA at 115200 baud, each >byte you send is surrounded by two bits as part of the async >protocol. Which means the real maximum data delivery rate to your TA >is around 90000 bits per second. A rather poor usage of a 2B channel >call, which can handle 112000 or 128000 bps. Of course, this is totally dependant on the primary use you put the ISDN line to. I have an ISDN connection to my work and for a while it was only 64K due to incompatability problems. I found that quite usable for several reasons. One, most of my time is spent typing and interacting with computers over the link. Comparitively little is spent doing huge transfers. As I pay no connection charge to connect to my work, the speed of a transfer is largely irrelevant, as I can always do something else while transfers occur in the background(like read news), and in testing I found that even with 3 ftp sessions running from a host directly connected to the router on the other side of my connection, inter-character delay was still completely acceptable, with none of the problems you get with a modem connection. Another consideration I've found is that unless you're a night owl, even with 64k your speed for ftp and web browsing is more limited by other parts of the net. I've found during weekdays that I average around 2-3k/sec which is only slightly better than the speed I got with a 28k modem, possibly due to improved ack turnaround time. Of course, now I have a full 128K connection, it is nice when I hit a site that can actually send to me at full speed. -- John Henders
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