From inside (document excerpt):
Instruction Manual EJ-41U Terminal Node Controller Unit Thank you for purchasing this fine Alinco product. This unit enables data communication when it is properly installed in designated Alinco transceivers. Please read this manual, print the contents if necessary, and keep this disk for future reference. Since this device is capable of being used in commercial applications, some of the pages in this manual are intentionally left blank to accommodate those uses in other regions.
Transceiver Radio Manual Free Download. Radio Communications Operator’s Guide. Free VHF radio Instruction and Manual Download PDF.
Although we attempt to explain the features of this unit in a simple and comprehensive manner, unless you have some knowledge about packet communications and APRS, you may have difficulty understanding the contents of this manual. We apologize, but Alinco cannot provide basic information of how packet and/or APRS works in general. Please consult your favorite Ham radio stores for books on the subject and/or web-sites that support your area of interest regarding those communication modes. You can explore the exciting world of data communication by yourself, and we believe that this is a most interesting part of the king of hobbies, Amateur Radio. APRS® is a registered trademark of Bob Bruninga, WB4APR Notice · This unit should be used with ALINCO transceiver DR-135T/E. · The memory of all settings of the unit are retained by the built-in lithium battery. If they go back to the default, the battery might be consumed. In that case consult the dealer. Accessories The accessories listed below are included. Check that all of them are found before using.