Communicating Application Specification
by Lloyd Borrett
Technical Cornucopia, MayJune 1989
Traditionally, some barriers to effective PC
communications have existed between applications and
communications software. In contrast to the ease of sending
a document to the printer, users who wanted to share a
document or data with others had to exit their applications,
and call up communications software. Then they encountered a
different set of problems.
Users need to conduct their business with clients,
suppliers, managers, peers, remote employees, consultants
and others. These various groups make up a user's
Paper systems memoranda, letters and air mail shipments
are generally accessible to everyone, but they are slow by
electronic standards and do not provide information in a
form that is easily manipulated by the recipient.
Electronic delivery systems modems, LANs, E-Mail and
telex can provide near instantaneous communication, but
individual network members will seldom have access to the
same electronic communications tool. LANs are the most
restrictive since they require hard-wiring of all network
members. But even 75 percent of businesses still lack PCs.
A better way
In 1987 Intel began to envision the integration of
applications software with communications hardware and
software for unprecedented ease of use in reaching all
members of the individual network including both PC and
In this model, PC communications would be as simple as
sending a document to the printer. For example, a user would
complete a document and then make a new menu or function key
selection in his application to send the document to, say,
10 offices according to a pre-programmed schedule
including five PCs, three FAX machines and two PC/modem/LAN
systems. Or two users in different locations would establish
a personal E-mail system at a fraction of the cost of a
local area network.
The user would send and receive files be they word
processing, graphics, spreadsheet or database files to and
from other PC users within his standard application
software; there would be no need to go to a special
communications program except to maintain "electronic
address book" information on recipients.
And the recipients would not need matching communications
software or hardware; a single communications product could
transmit data to any telephone-based communications hardware
(FAX, modem, voice mail, etc.). The document or file would
arrive just as it was sent formatted within the
application, ready for manipulation by the recipient without
And perhaps most important, the communications system
would be an intelligent one, that is, it would offload the
work of communications processing from both the user and the
PC's CPU to the communications hardware. Communications
processing would be executed in the background, while the
user and the CPU were free to return to the application file
or to any other computer function.
An intelligent communications add-in board would provide
a solution consistent with this Intel vision. As both the
installed base of PCs and the sophistication of PC users
continue to increase, the market for such communications
boards also increases.
Until now, the lack of consistent industry standard
protocols has been a prime stumbling block to achievement of
this vision of intelligent, transparent PC communications.
A new communications specification
Intel joined with Digital Communications Associates Inc.
(DCA) to develop a software standard to support transparent
PC communications. In August of 1988, Intel and DCA
announced the first fruits of that effort: the DCA/Intel
Communicating Applications Specification Version 1.0, or
DCA/Intel CAS. It is a programming specification in the
public domain, allowing developers to turn business
applications into communicating applications using a
straightforward, standard implementation.
To this project, Intel brings its expertise in PC
coprocessing. DCA brings expertise in PC-to-mainframe
communications with its IRMA and Crosstalk products. Intel
and DCA plan to develop compatible CAS updates that will add
interfaces to modems and to DCA's IRMA board, ensuing that
PC-to-mainframe communications will be a significant element
in the heterogenous communications environment being
established under CAS.
These advances will allow users of host-connected PCs to
employ a single interface to:
- Communicate directly with mainframes,
- Share that information with remote PC users and FAX
machines connected only by telephone lines, and
- Instantly download communications and continue with
Independent PC software developers endorsing the
specification are Alcom Incorporated, Ashton-Tate Corp.,
Borland International Inc., Conetic Systems Inc., Lotus
Development Corp., Microsoft Corp., Novell Inc., cc:Mail
Inc., Symantec Corp., WordPerfect Corp. and WordTech Systems
Inc. Most of these software developers already have
incorporated CAS into their popular PC software.
How CAS works
CAS provides an easy interface for software developers to
add communications to existing applications as well as the
ability to communicate with non-PC users. E-mail software
developers, for instance, are using the specification to
extend the power of local area networks (LANs) by providing
a bridge between networks, high-speed links to support
remote users and a facsimile gateway to people who don't
The new programming specification includes core functions
of communications scheduling and execution to allow software
developers to implement communications the way they
currently implement printing transparently (that is,
without the user having to exit the program).
The CAS is implemented via two software components a
Resident Scheduler and Transfer Agents. A software developer
using CAS initiates a communication request in his
application by calling a Resident Scheduler and indicating
the target (distribution list), transmittal document(s) and
desired time of communication. The Resident Scheduler can
access all available communications technologies, which
shields the applications developer<197>as well as the
ultimate user from the details associated with those
The Resident Scheduler takes information from the
application and "looks up" information in the electronic
phone book to determine the appropriate communication method
and route to each destination.
If the Resident Scheduler is the communications "brains"
of the CAS, the Transfer Agent is its "legman". Consisting
of a set of code to connect, transmit and disconnect from
the recipient, the Transfer Agent ensures that data is
transmitted reliably and reports status information to the
The Transfer Agent may execute on the host microprocessor
or on intelligent communications hardware, if it is part of
the system. Downloading the transfer agents from the
microprocessor to intelligent, dedicated communications
hardware is what allows communications to take place in the
background, while the CPU takes up further tasks. It also
allows the architecture to support multiple Transfer Agents
and to easily update existing Agents.
Intel was well-positioned to lead the development of DCA/Intel
CAS. It followed the same inter-company cooperative process
it developed with Lotus and Microsoft to create the
Lotus/Intel/Microsoft Expanded Memory Specification. That
specification did for expanded memory boards what the DCA/Intel
CAS is doing for communications products. It provided the
foundation upon which systems vendors could provide
compatible products to solve a basic problem in PC use.
In its initial release, CAS supports communications
specifically from an intelligent communications coprocessing
board Intel's new Connection CoProcessor board.
The Intel Connection CoProcessor Board
The first intelligent communications hardware product to
support DCA/Intel CAS is Intel's Connection CoProcessor
board. This communications coprocessing board and
accompanying communications software allows its users to
exchange files including binary data, graphics and text
E-mail and FAXes with other Connection CoProcessor board
users at a rapid 9600 bits per second. They can also send
FAX and E-Mail to all Group III FAX machines and receive
FAXes from them.
The Connection CoProcessor board is compatible with IBM
PCs, XTs, ATs, 80386 systems and compatibles, and is
hardware ready for OS/2. It uses a 10 MHz 80188
microprocessor and 256 KBytes of memory to download
communications processing from the main CPU, freeing that
microprocessor and the user for other tasks.
With this communications coprocessing board, users avoid
the complicated protocols and logistics of modem
communications and receive feedback on transmission status.
Both the transmitting and receiving PCs can be unattended.
The product is four to eight times faster than traditional
modems in file transfer mode, and that can produce
significant savings in long distance telephone charges.
Users can access the Connection CoProcessor board through
the simple Intel communications application. That
application also serves as the electronic phone book for up
to 999 stored distribution lists with up to 999 names in
With add-ins and releases for popular software packages
including Lotus 1-2-3, SideKick Plus, WordPerfect, and Q&A,
Intel Connection CoProcessor board users will be able to
send files and FAXes via simple menu or function key
The Intel Connection CoProcessor is just the first of
many hardware products that we will see exploiting the power
of DCA/Intel CAS. Already most of the major software
developers have shown their support for CAS by actually
releasing products that use CAS.
This will have the most impact initially in the facsimile
board market. You now have a choice of purchasing many
different facsimile boards, each with their own unique
interface to software (usually just an ASCII file), or the
Intel Connection CoProcessor board which already supports
Certainly, software developers have signalled they would
prefer to see one common interface for all communications
products by the way they have so rapidly come forward with
support for CAS. During the next six months we believe
support for DCA/Intel CAS will increase dramatically.
We believe that eventually most facsimile board
manufacturers will be forced to modify their hardware and
software to support the DCA/Intel CAS specification. And we
see the manufacturers of modems and PC-to-mainframe products
being pressured to do the same.
But best of all we see the opportunity for exciting new
software applications that will make it easier for us to
communicate with each other, in ways not dreamt possible
Saturday, 15 October 2011