whwb@ciba-geigy.ch (Hans W. Barz) (12/12/90)
I'm looking for a program, which delivers a virtual, serial device on a DOS PC. This device should run on top of a telnet session. The only possibility to implement that seems to be the IBM Asynchronous Connection Server Program (Vers. 2.0). The Client on the PC is done by a Crosstalk session on top of NETBIOS. This NETBIOS session runs to the Asynchronous Connection Server running on a dedicated PC. This dedicated PC can then connect this session to telnet. I do not like this way since I need a special dedicated PC for it. Has somebody else a better way of doing it ? Hans W. Barz, R.1045.3.34, CIBA-GEIGY, 4002 Basel, Switzerland Internet/uucp-Mail: whwb@CIBA-GEIGY.CH X.400: C=CH;A=ARCOM;P=CIBA-GEIGY;OU=CHCGBS30;S=BARZ;G=HANS;I=W phone: +41/61/6974520 fax: +41/61/6973288
nestor@hls.com ("Nestor A. Fesas") (12/17/90)
> > I'm looking for a program, which delivers a virtual, serial device on a > DOS PC. This device should run on top of a telnet session. The only > possibility to implement that seems to be the IBM Asynchronous Connection > Server Program (Vers. 2.0). The Client on the PC is done by a Crosstalk > session on top of NETBIOS. This NETBIOS session runs to the Asynchronous > Connection Server running on a dedicated PC. This dedicated PC can then > connect this session to telnet. I do not like this way since I need a > special dedicated PC for it. > > Has somebody else a better way of doing it ? > > Hans W. Barz, R.1045.3.34, CIBA-GEIGY, 4002 Basel, Switzerland > Internet/uucp-Mail: whwb@CIBA-GEIGY.CH > X.400: C=CH;A=ARCOM;P=CIBA-GEIGY;OU=CHCGBS30;S=BARZ;G=HANS;I=W > phone: +41/61/6974520 > fax: +41/61/6973288 > Such a "virtual serial device" service directly connecting a PC to a host is available from several vendors offering PC based TCP/IP products. There are a number of interfaces which can be used for this (e.g. Interrupt 6Bh, Interrupt 14h, etal), but the most popular seems to be Interrupt 14H (I14 for short), probrably due to its simplicity in both implementation and use (an interrupt is issued for each character read/written and the interface supports little more than character read, write and get status calls). This works fine for most situations, but limits performance when lots of data is being output to the screen (of course, on faster machines, the limit is less noticeable). We provide an I14 capability as do Wollongong and FTP software. The implementations may differ somewhat but the net effect (no pun intended) is much the same. FTP Software provides an I14 interface as part of their PC/TCP product. The program providing this feature, TNGLASS, can be invoked with a parameter to specify a third party terminal emulator that supports I14. Data is then shuttled between the host and the PC using telnet. I'll refrain from commenting on Wollongong's INT 14H capability since I know little about it other than it exists. I'm sure Leo will come to my (his?) rescue and fill the void. Regarding our own product, ProLINC, we support I14 for both TCP and LAT. A mix of multiple TCP and LAT sessions are concurrently supported (up to four total sessions) as long as the interface to the stacks is synchronous, i.e, an interface where the stacks get to run to completion when performing a read or write to the net. Consequently, if your terminal emulator supports multiple concurrent sessions in this manner (Kermit, Smarterm 340 and others do), you can open one or more connections to your LAT and TCP hosts simultaneously. Note that in the TCP case, Telnet is used to communicate with the host, and in the LAT case, we run directly on top of the protocol. Finally, since our I14 redirector is a TSR, it can be used by Windows specific terminal emulators such as Future Soft's Dynacomm. Nestor A. Fesas, Jr. Hughes LAN Systems nestor@hls.com 1225 Charleston Road (415)-966-7473 Mountain View, CA, 94043