Off-The-Wall Data Communications
Original Publication Date: 1989-Mar-01
Included in the Prior Art Database: 2005-Jan-27
This article describes a data communications link which will automatically switch between a hard-wired data link and a portable battery-powered radio link. A support terminal which comprises a battery-powered computer requires data communications with a host for proper operation. When the terminal is "on the wall", it will recharge its batteries and can also communicate with the host computer, as illustrated in block diagram in Fig. 1. When the terminal is later used in a portable mode, communications must automatically switch to a battery-powered radio link, as illustrated in Fig. 2. This is accomplished by sensing an "off-the-wall" (OTW) signal which is controlled by a jumper in the hard-wired connector. (Image Omitted) Fig. 3 shows the OTW detection circuitry.