For the last two years, the Editors have been recommending X.400 conformity for electronic mail, including its Use for local library systems. Upon hearing that Hewlett-Packard would charge $18,000 for the option on its large minis, a library has asked us to elaborate on the value of X.400. We're happy to do so.
The problem with electronic mail (E-Mail) today is that the service is not universal. It is like having one's telephone calls limited to those served by the same telephone company. The purpose of the X.400 standard is to liberate users from E-Mail vendor-dependence. The X.400 E-Mail standard is a collection of protocol recommendations that cover not only the format of E-Mail messages but also how different systems communicate with each other. X.400 is a fairly comprehensive E-Mail standard that takes into account a number of different kinds of communication. The body of the message can include text, fax images, encoded voice messages, videotex, and “specialized” formats (which allows X.400 to transport data in a format not defined in the specifications, such as PC graphics files or spreadsheet data). X.400 puts no theoretical limit on the size or quantity of enclosures in a message. If X.400 were to be widely adopted, almost any E-Mail user would be able to communicate with any other.
X.400 networks don't require one particular kind of cabling or communications protocol, although a popular implementation of X.400 is through centralized packet-switched telecommunications networks such as Telenet or Tymnet. Any user on one of these networks can send mail to any other; all a sender has to know is the recipient's electronic address.
X.400 messages can be related to other messages to make it easier to track a multimessage conversation. For example, a message can have a “forwarded” indication or an “obsoleting” indicator, which tells the receiving system that the current message supersedes a specific previous message. It can also have a “cross-reference” field, which can refer one message to a previously sent message.
Most messages will have a “subject” field. They can also have a “priority” level, from 1 to 3, which tells the system how quickly the message must be transmitted; an “importance” flag, which lets the recipient know how urgent the message is; and a “sensitivity” notation of personal, private, confidential, etc.
The one thing the X.400 specification lacks is a comprehensive E-Mail directory; if you want to send an X.400 message, you have to know the E-Mail address of the recipient. The emerging X.500 Directory Standard will provide such a directory.
A standard such as X.400 can only be successful if it is adopted by the majority of E-Mail vendors. To date, a consortium of 22 E-Mail software vendors have pledged support for this standard, including microcomputer software vendors like CC Mail, Lotus, Indisy (a Novell affiliate), and 3Com, as well as more diversified vendors such as AT&T, British Telecommunications, DEC, and Telenet Communications. Called the X.400 API Association (APIA), the organization has gone so far as to agree on a specification for a series of Application Program Interfaces (APIs) in the C language designed to make development for X.400-compatible programs easier. These APIs will handle the data conversions necessary to put an E-Mail message in a format that is compliant with the X.400 specifications. Once the APIA finishes writing APIs for the latest X.400 standard, it plans to tackle the X.500 Directory Standard.
We don't necessarily insist upon implementation of X.400 at time of installation. However, a library should obtain a commitment that X.400 support will be available when needed and at what cost.
E-Mail was around long before the X.400 specification was designed or even conceived of, so there are many older E-Mail systems that don't conform to the X.400 model. In order for one of these older-style E-Mail networks to communicate with an X.400 system, an E-Mail gateway is needed. One company, Soft-Switch, Inc., of Wayne, Pennsylvania, makes a series of gateway products that translate E-Mail messages between the major entrenched vendors like H-P, Data General, and IBM. Soft-Switch products will translate a message from any of these protocols to X.400 and back again, enabling almost any existing E-Mail system to communicate with almost any other. However, current prices will not be much lower than those quoted by computer companies.
[Contact: Soft-Switch, Inc., 640 Lee Road, #200, Wayne, PA 19087; (215) 640-9600.]
