Following the asynchronous AppleTalk™ technology developed at Dartmouth College, Sand Hill Engineering Inc. of Geneva, Florida has developed a new network reactor which is capable of emulating the AppleTalk™ bus. Although not limited to Macintoshes™, this device is transparent to most current Macintosh applications which depend upon AppleTalk™. Any Macintosh™ with a 1200bps or higher speed modem can dial in to another modem and sign on to the reactor as an asynchronous AppleTalk™ port and will then appear to the caller Mac and all other Macs already on the network that there is a new subscriber on the net.
There are two installations of this system at press time, the most interesting of which is at the Orlando, Florida offices of Peat, Marwick, Mitchell & Co. The other is at Sand Hill in Geneva, Florida. Macintoshes™, PC's, printers, Laserwriters™ and modems are connected to multiple network reactors which will ultimately provide service to more than 80 devices at the Peat Marwick offices and currently serves 15 nodes at Sand Hill.
Currently running are unmodified AppleTalk™ applications on Macintoshes and Symphony™ communications and printer applications on PC's. When it is necessary to transfer spread sheets or files from Mac to PC and back, other standard software products such as MacLink™ by .... provide the intelligence at both ends to convert formats and formulas.
Peat Marwick and Sand Hill are now using Intermail™, an electronic mail and file transfer program for the Macintosh™ by Interactive Network Technologies of Waban MA. By attaching 2400 baud modems to a reactor at the Peat Marwick offices and dialing another modem at Sand Hill, it is possible for the asynchronous Appletalk™ networks to appear to be one. This connection may be temporary or permanent, or at higher speeds over dedicated lines, and is compatible with most of the newer error-correcting and speed-switching modems.
Thus, it is possible at this time for an accountant to be at a clients office or at home, dial into the office, sign on as an AppleTalk™ node, send and receive messages or files from others in the office or anyone else who may also be dialing in. He or she may print to a shared LaserWriter™ or other printers, and may link with and share files, with PC's and clones. PC's dialing in may link to other PC's or devices, contending for shared devices such as modems, or spooling data to shared printers.
Although only a pilot program in Orlando, ultimately multiple offices of Peat Marwick Mitchell may be joined into one apparent network. Macintoshes and PC's will be able to 'converse' with other Macs and PC's, file servers, and any other device that has an asynchronous RS-232 port which is connected to any network reactor which has a link (or links) to other reactors. Automatic routing is provided by the reactors for a theoretical address space of 16 million nodes, and AppleTalk™ devices never suffer collisions.
As an asynchronous system, the reactor concept purports to be more compatible with personal workstations (and even mainframes!) where even with high speed disks, applications need a little breathing room for processing. The reactor by Sand Hill supports serial speeds up to 19.2 Kbps, and provides modular interface to parallel devices.
Yet to be developed is an asynchronous AppleTalk™ interface for the MS-DOS world. Since one of the simplest parts of the design of any network interface is the choice of command codes and the format of the message, it should be forthcoming that developers add such an option to their networking software.
Currently available only to developers and users with in-house support, Sand Hill Engineering is soliciting aid in marketing and sales of the as yet un-named device.
For anyone wishing to dial in to the Sand Hill reactor, a demonstration program and instructions are available in the Macintosh, PC, and Telecommunications data bases on Compuserve™ and Genie™.
For further information please contact Michael Ferguson at the address or phone below.
