Or possibly check with Randy Kennedy; as a firefighter he may have access to the docs and could send required pages. GWS
________________________________ From: altusmetrum <[email protected]> on behalf of danno <[email protected]> Sent: Friday, March 15, 2019 9:18 PM To: Altus Metrum Subject: Re: [altusmetrum] TeleLCO You'll have to register on the site, but you can find NFPA 1127 at https://www.nfpa.org/codes-and-standards/all-codes-and-standards/list-of-codes-and-standards/detail?code=1127. If that link doesn't work for you, you can search 1127 from https://www.nfpa.org and then click on "more information about..." from the page for ordering the book. Dan Crank On Fri, Mar 15, 2019 at 10:11 PM Bdale Garbee <[email protected]<mailto:[email protected]>> wrote: "David W. Schultz" <[email protected]<mailto:[email protected]>> writes: > Both NFPA 1122 and 1127 require that launch systems include a removable > safety interlock in series with the launch switch. TRA uses NFPA 1127 as > their safety code and NAR requires following the NFPA codes at all NAR > launches. So this is a problem. I wasn't aware that a removable interlock was an explicit requirement. I just looked and couldn't find the current NFPA text anywhere online. I'd like to read the actual text... any idea where I can find it? > The fix is to replace the silly guarded toggle switch with a key > switch for safe/arm. Right, pretty easy change. I'll look at the details tomorrow. > Put a lanyard on the key so the LCO can hang it around his neck when not > in use. (Stash a spare key inside the case.) Sigh... all part of the reason I personally detest key switches. My observation is that key switches get turned, but the key rarely gets pulled out in practice. But .. [sigh] .. rules are rules. > Those switch connections make me nervous. They connect unprotected GPIO > pins to parts that are being handled by the user. Sure the switch body > will provide some protection from ESD but how much? A series resistor > would help a lot. Large enough to limit currents in the ESD diodes on > the GPIO pins but small enough to work with the internal pullups. Sure. In several years of use, we've seen no issues with zapping the SOC's in-built ESD protection on the protos, but resistors are cheap and I can easily add them to the board revision I'm preparing to send out to fab. Thanks for the suggestion. > Oh, I thought that the FCC prohibited encryption for amateur radio: > 47 CFR 97.309(b) Has that changed? 97.309(b) does not apply because we're not encrypting the content, thus we are in no way "obscuring the meaning of any communication". What we're doing is appending a crypto checksum to each packet to authenticate the link. That's been a common mechanism on amateur radio control links for a long time. The closest thing I can find to an official pronouncement about this is in the ARRL comments in response to RM-11699, which they opposed. In those comments, they indicate that conversations with the FCC led to agreement that encryption for authentication on things like repeater control links was already allowed, and thus not a reason to accept the request that lead to that RM. I'll note in passing that there's also 97.215(b), though I don't think the FCC had model rockets in mind when discussing telecommand of model craft. Sure feels like an analogous use, though. Bdale -----BEGIN PGP SIGNATURE----- iQIzBAEBCgAdFiEEhHDyCwYlkhh8unuzOpNhlsCV2UEFAlyMaUUACgkQOpNhlsCV 2UH5YhAAvZgOpMXkIoeiJ6io9efj7eT47sw6CqFjjYaL2K/8bxA7oZbpikjEUFhx CSCe87eS9MEu6rbw6I0kJcfe/y4tVRjrhSUiMOkm9mGDyHWLJvePNkL0ceyW10cW xyG7rBlthhJNc4XmzH5vI2VrRRpuB+36M8P9hMDZEvlfNr2E85VCXl9BX8EgRoqX 1EHT+nlZa/yO+vhEq4MTrQ0oLLqC1Rm+Z8BT2lefygAyDFE03laCT4qcz+wM0Vwk 5Q8J71H+3Eq0qQmweU/I7nrBYsMGdgGEGiPyYczi2iVU7GsbVOJ2Tgi8awEIksTU HrwhP3i6YjEvZNGXj4R6mM9d2AccjlWRcc+E1E9n2ogH6H5MFZ15b1GI/4T36tyT GjWJhBb81vRzCjhbyAXd5Y5YjXWUz6TYiUW3hqH+PemGEmavkJuVpAll7nCI6YjU 8UkbtSR7JH92BeECPFdXBtYMEbEP9nBLwCS02Pnh2IfnQooTQJWn+ouRLrfmcgjN DTvTjWHOYbjbJpHfGa9IUlqDTO+94C2+hakeQnFfMtkO4QiJX0A62v2vVJwI/TC1 sObzq034tH8ClDE4VGZpdHhq+X4AZ6gbJPzOi2mAtevfKS/ZpxMVq5ZrE6Hr4k/v qHuikrZTZ1vnmraqEw2jVjCP4OUsi4hfUZVEM5Bl6AF09G14GrU= =AY2F -----END PGP SIGNATURE-----_______________________________________________ altusmetrum mailing list [email protected]<mailto:[email protected]> http://lists.gag.com/mailman/listinfo/altusmetrum
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