A portable adapter that provides non-repudiable telecommunications services to bar-code reading hand-held computers and palm-top or tablet-type mobile computers is disclosed. The adapter provides supplemental power supply and processing capacity that supports API communications functions, such as interactive voice recognition, conference calling, data encryption, VoIP packetization and other signal-format conversions that are not implemented on mobile computers. In particular, the device automatically logs IP packet identifiers and DOV dialing and status signals, without the user having access to edit this information, thereby providing a "non-repudiation" record of all communications. The adapter also supports intensive use of the host computer's serial port by supplementing the power available from the host computer's battery, or replacing that battery with a connector. For plant inspection and inventory auditing, ground-based cellular communications are implemented for supporting on-site work, including conference calling to discuss apparent pilferage or imminent safety hazards, and removable WORM recording media for documenting these discussions. For repair shop use, a standard phone jack or 10-base-T connector allows the device to upload engine test-data, with reports or estimates dictated by the mechanic to the repair shop's LAN server. For hospital use, the device includes removable WORM media for logging patient test results and examination reports. The hospital device also uses a dedicated local-area RF or IR transmitter, with location-specific encryption, to protect the privacy of lab reports received by the device, and to limit use of these devices to hospital's own premises.