buz@umich.UUCP (G. D. Buzzard) (08/20/85)
I have a question concerning the connection of an appletalk network to other networks. To put this question in perspective, I've just recently started using macs, so I've looked at most of the applicable Inside MacIntosh and Inside Appletalk documentation (I think) but don't pretend to have a thorough understanding of it. My problem is as follows. I would like to program a dedicate a MacIntosh on an appletalk network (of 10 to 25) to serve as a gateway server to a communications processor (on another network) that speaks X.25 over an HDLC (used like SDLC) interface. The idea is to provide several virtual circuits so that multiple apple users can logon to a remote host thru a single synchronous connection. I don't have the details yet, but I beleive the internetwork HDLC transmission speed will be <= 57600 bps. The first question that comes to mind is can the Mac hardware (Zilog 8350, etc., I understand) be used to concurrently provide HDLC service to both appletalk (thru the printer port?) and another system (thru the modem port?)? Secondly, if the above is possible, are there any existing software routines that can be used to setup the hardware, build frames, handle sequencing, etc? It appears as though the Mac serial driver software does not handle synchronous communications. Can parts of the appletalk driver be used? Finally, does this scheme sound reasonable, or are there better ways to build this mousetrap? For building a different mousetrap the constraints are that it be rather inexpensive (what's new) and use off the shelf hardware if at all possible. Any direct reaponses will, of course, be appreciated. Also, suggestions for places to begin looking for answers myself are welcome. I seen a lot of mac documentation but not much of it seems applicable to this task. Thanks Greg Buzzard ihnp4!umich!buz