A number of companies periodically issue evaluations of electronic typewriters. Among the most useful:

Buyers Laboratories Inc. is an independent testing organization that describes itself as a "commercial Consumer's Report. " There are three ways to buy their typewriter reports. They are available as part of BLI Reports on Office Equipment, which consists of loose-leaf volumes, supplemented every other month, plus three monthly newsletters ($475). You can subscribe to Typeline for $125 a year, which brings you the section of the larger service that deals with typewriters, plus, in alternate months, a newsletter and more test reports. Finally, you can buy BLI Reports on Typewriters, for $85, which does not include newsletters or updates. Buycrs Laboratories Inc., 20 Railroad Ave., Hackensack, NJ 07601; (201) 488-0404. Datapro Research Corp. issues a periodically updated report All about Electronic Typewriters, that gives an overview of the market. The current issue includes tables listing specifications of 51 models from 15 manufacturers ($19). The report is excerpted from Datapro Reports on Word Processing, a service that, for $5 15, includes a two-volume, loose-leaf report, monthly updates and newsletters, plus unlimited access to Datapro's telephone consulting group. Datapro Research Corp., 1805 Underwood Blvd., Delran, NJ 08075, (609) 764-0100.

Seybold Publications Inc. has just is sued Seybold Report on Electronic Typewriters. It is a comprehensive evaluation of 13 models from five manufacturers; these models cost less than $2,000 cach. The report includes a summary of features, a section on needs analysis, and a "Best Bet" list. Seybold plans future issues, which will provide updated information on the under-$2,000 class and evaluate models costing $2,000 and more. The report is $75 for those already subscribing to the Seybold Report on Office Systems ($96 per year for 12 issues, $150 beginning in November) and $100 for nonsubscribers. Seybold Publications Inc., Box 644, Media, PA 19063, (215) 565-2480.

Oppenheim Derrick & Co.'s What to Buy for Business recently devoted an issue to the electric and electronic typewriter market. The report includes "good value" recommendations and lists target prices reflecting the largest discount you can expect on single purchases. Oppenheim Derrick & Co., Box 1783, Fort Collins, CO 80522; (303) 223-3477. Annual subscription (12 issues) $65, prepaid Typewriter issue only, $15 if you mention INC