If your job puts you in contact with a lot of people,

a personal computer loaded with contact management software can help you keep track of all of them.

I've taken a look at four contact management programs that run on IBM and compatible computers with 640 kilobytes of memory and, in most cases, a hard disk.

ACT, version 2.0, $395, comes from Contact Software International Inc. in Carrollton, Tex., 214-418-1866,. BizBase, version 2.1, $395 for its "gold" hard-disk model and $99 for the less-powerful single floppy disk "silver" version, is offered by Creagh Computer Systems in Solana Beach, Calif., 619-259-7174. The Maximizer, version 2.1, $295, from Richmond Technologies & Software Inc. in Burnaby, B.C., 604-299-2121, has undergone two significant upgrades this year. A network version sells for $695. Performer, $295, comes from Performer Systems Inc. in Alhambra, Calif., 818-300-8570.

All four have basic features in common. They let you keep detailed lists of the people and companies you contact. They schedule calls, meetings and other activities. You can automatically prepare letters, memos, invoices and other forms, properly addressed and personalized with your contact data.

You can search through your lists of data in various ways, such as the person's name, company name, city, business category, last date of contact and next scheduled contact.

Each has built-in word processing to write letters and other documents. ACT and Maximizer include spelling checkers. Once written, letters can be used over and over, with appropriate name and address supplied automatically.

They all will place telephone calls if your computer has a modem and will keep track of your expenses. All except Maximizer can be suspended temporarily so you can run other software and then return to the same point you were when you left.

ACT is a program for people who can't or don't want to type. Nearly everything, including sending letters or virtually any other document or form, can be accomplished with just a few keystrokes. Every part of the program is tied to the contact records, which provide basic identification data, plus 29 user-defined fields.

Entries for most data fields can be selected with a single keystroke from a pop-up list of entries commonly used, such as state or city names or business titles. Operations are selected from menus at the top of the screen, where they can be easily perused any time you can't remember what command you want.

Performer is a solid, middle-of-the-road program and is the quickest of the four to begin using.

Two screens full of data can be stored for each contact, which is typical of all these programs. Performer allows you to define 31 of the fields, with your own category names. Most fields have associated look-up lists in which you can store common entries, such as job titles or task categories.

BizBase Gold, version 2.1, is organized around a time management system that keeps track of all your activities. When the program opens, your day is displayed on a screen divided into four sections, labeled "recalls," "follow-ups," "calendar" and "task scheduler." Recalls and follow-ups are similar. You designate a recall when you want to call a client at a particular time for a particular purpose. A follow-up is scheduled for clients to whom you have already talked or mailed a letter or sent a shipment or whatever.

The appointment list suffers a serious limitation because the only times allowed are in half-hour intervals from 7 a.m. to 5 p.m. That is one of the few limitations, however.

BizBase gives you the ability to redefine most of the 50 fields of information it will store about each person. It also includes a word processor, a calculator and modem program. It has a cluttered appearance and is complicated. But if you are an experienced computer user and maybe have been thinking about creating your own contact management software, BizBase is the would-be hacker's delight.

Maximizer utilizes pop-up menus that sprout at various locations on your screen depending on what portion of the program you are using. But you will have to memorize the keys needed for basic functions because there is no on-screen prompting system.

Its organization is a little different, featuring a list of "clients," with subsidiary "contact" lists. Each client can be categorized under an unlimited number of "descriptions" that you create to make it easier to get back at entries in your list in various ways.

The bottom line on contact management is that any of these programs will make the task easier -- but only if you use them constantly.

Richard O'Reilly is a Los Angeles Times staff writer. Readers' comments are welcomed. Write to Richard O'Reilly, Los Angeles Times, Times Mirror Square, Los Angeles, Calif. 90053.