Bulletins from the Pacific Packet Radio Society - page 134

TAPR Activities by Den Connors KD2S

The TAPR terminal node controller beta test is finally upon us! We have ordered the parts for the PC boards, and Lyle- WA7GXD has populated one of the check boards, tested all of the required hardware and is ready to give the go-ahead for the 180 boards needed for beta test. Here's how it happened ...

Pete Eaton WB9FLW and Bill Reed WD0ETZ had been tapping the resources of St. Louis looking for a good P.C. layout facility and a group that could make our custom transformer. They were very successful with both tasks. The P.C. layout was sent to us in the first week of November, and after a careful look-see by Lyle, was modified and approved. The "final" layout arrived that weekend, and has again been checked. As the layout was shipped, Pete and Tom Brickey WB0WRK hid in a P.C. fabrication shop for a period of time, and out popped three extremely good looking "check boards", which are now in our hands here in Tucson. Also sitting down here is a copy of our transformer, with windings for +/- 12 volts as well as goodly quantity of +5 volts, after regulation. Lyle has put a board together, and he and Mark Baker will assemble a second unit later.

The final controller ended up being everything we've been promising, and quite a bit more. Lyle has included 24K of 2764 EPROM and 6K RAM on all boards going to test sites. The on-board Bell 202 type modem has had added to it a four-pole switched-capacitor audio input filter, and still has the built-in modem calibration circuitry. The off-board power supply circuitry is now entirely on-board, less the transformer and fuse holder. We did go 6809 of course, and kept simultaneous serial and parallel port capability (important for some linking experiments we're working on). The on-board wire-wrap area now has power and ground rails, with all three voltages available. It's quite a hummer. We'll be shipping out the boards with solder masking, special coating over the traces and silk screening for component identification. All cables and connectors will be included, less the non-standard radio connector. We hope to have completed shipping all units to Beta sites before the Christmas holidays, and we're currently on schedule, for a change.

( Please note that we don't sell these things for a living, but for those hams interested, we'll be coordinating efforts for further distribution with all of our beta site coordinators.)

And protocol ... That brings up the software activities, which are now as geographically distributed as the hardware effort. As noted elsewhere in this issue, the AMSAT packet meeting held in October brought forth a standard protocol for the AMICON effort. The level 2 ( data link layer ), protocol chosen is not compatible with the current TAPR dynamic-addressing software being developed by Marc Chamberlin WA7PXW and Dave McClain N7AIG. The TAPR/DA routines are much more efficient at sending short packets, shaving 19 bytes off of the packet header in a repeated message, leaving more milliseconds for other transmissions. No

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