At 11:41 AM 8/28/2006, you wrote: >I'm willing to believe that the timing tolerances in -tor modes >are so tight that ordinary PC operating systems cannot cope with >them the way a dedicated processor can. What I don't understand >is why the tolerances need to be so tight. The transmitter sends >a packet and then listens for an ACK or NAK. Why can't it wait >arbitrarily long? > >There are protocols for wire transmission e.g. IBMs Bi-Sync >which worked in the days of modems that could only transmit in >one direction at a time. These used old slow computers to >run the protocol.
That is pretty much the way it is with the ALE DTM ARQ, DBM ARQ protocols and most of the ARQ protocols on the high speed MIL-STD-188-110x PSK serial tone modem. The FSK one's will run on just about any CPU and PC Sound Device when an 8Khz sample clock is used. The '188-110 modem is a CPU/Memory hog and requires a 9.6Khz sample clock, to have both the FSK/PSK modems active at the same time on the same PC Sound Device you need a common ground so 48Khz is used as its dividable by both 8k and 9.6k. We have a version of MARS-ALE called "Legacy Edition" that only has the FSK modem at 8Khz and then both modem at 48Khz, thus the MARS-ALE LE version runs on a 386 and Windows 98SE and that DBM ARQ is a real performer at a raw 125 baud and deep interleaving. /s/ Steve, N2CKH Need a Digital mode QSO? Connect to Telnet://cluster.dynalias.org Other areas of interest: The MixW Reflector : http://groups.yahoo.com/group/themixwgroup/ DigiPol: http://groups.yahoo.com/group/Digipol (band plan policy discussion) Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/digitalradio/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
