27313853@WSUVM1.BITNET (Wim Bonner) (04/03/88)
I beleive the reason for the pauses in transmission with the HST modems are due to the single duplex nature of the modem. Each time you have to switch directions in the flow of data, the modems have to agree to stop, and send in the other direction. I know that there is a version of Zmodem Available that is specifically written for use on the HST modems. It minimizes direction changes. Wim Bonner (King-Rat) The Loft - (509)335-7407 - 300/1200/2400 - 24hrs/day - PCboard 12.1/d Acknowledge-To: <27313853@WSUVM1>
davidsen@steinmetz.steinmetz.ge.com (William E. Davidsen Jr) (04/04/88)
In article <8804020147.AA07896@ucbvax.Berkeley.EDU> 27313853@WSUVM1.BITNET (Wim Bonner) writes: >I beleive the reason for the pauses in transmission with the HST modems >are due to the single duplex nature of the modem. > >Each time you have to switch directions in the flow of data, the modems >have to agree to stop, and send in the other direction. Could you clarify this?? The info on the HST which I have clearly states that there is a 300baud reverse channel to allow acks and naks to travel back without reversion the line. It also keeps up with most typists so that the high speed may be used for screen updates. Is the info they send out incorrect, or are you describing some other occurence? I think Keith Peterson has these modems, perhaps he will comment. -- bill davidsen (wedu@ge-crd.arpa) {uunet | philabs | seismo}!steinmetz!crdos1!davidsen "Stupidity, like virtue, is its own reward" -me
marc@mfbbs.UUCP (Marc Randolph) (04/12/88)
In article <8804020147.AA07896@ucbvax.Berkeley.EDU> 27313853@WSUVM1.BITNET (Wim Bonner) writes: >I beleive the reason for the pauses in transmission with the HST modems >are due to the single duplex nature of the modem. Data CAN flow in both directions at the same time. According to the HST manual, page 1-1: ..."data flows in one direction at 9600 bits per second and 300 bits per second the other". >Each time you have to switch directions in the flow of data, the modems >have to agree to stop, and send in the other direction. The only switching that takes place is who has the high speed channel and who has the low speed channel. If the modem with the low speed channel has a large amount of data to send, the channels will switch around so the large amount of data can get through quicker. >Wim Bonner (King-Rat) >Acknowledge-To: <27313853@WSUVM1> -- --- Marc Randolph UUCP: ...!rutgers!pbox!romed!mfbbs!marc FidoNet: 170/329 or 170/220
grr@cbmvax.UUCP (George Robbins) (04/15/88)
In article <5060@mfbbs.UUCP> marc@mfbbs.UUCP (Marc Randolph) writes: > In article <8804020147.AA07896@ucbvax.Berkeley.EDU> 27313853@WSUVM1.BITNET (Wim Bonner) writes: > >I beleive the reason for the pauses in transmission with the HST modems > >are due to the single duplex nature of the modem. > > Data CAN flow in both directions at the same time. According to the > HST manual, page 1-1: ..."data flows in one direction at 9600 bits per second > and 300 bits per second the other". Unfortunatly, with respect to uucp, the forward to backward channel ratio is 70:6, meaning that the modems 32:1 ratio isn't adequate for the purpose. I don't know what the modems algorythms are, but it's quite possible that it may decided to change directions if the "fast" side is inactive, and the slower side has data flowing at a > 300 baud rate. In a sense, this is a software problem, as uucp could be modified to use larger packets or only send acknowledgments for the most recently received packets, however these changes are not easily effected without access to the uucp source code. -- George Robbins - now working for, uucp: {uunet|ihnp4|rutgers}!cbmvax!grr but no way officially representing arpa: cbmvax!grr@uunet.uu.net Commodore, Engineering Department fone: 215-431-9255 (only by moonlite)