Methinks that I'll try for an identical model on the cheap at eBay, then try sending That back for credit. Can't imagine their troubling to look at its MAC address, though I could be wrong.
In that manner, Nothing gets unplugged.
(Was informed by Install techs that, merely unplugging modem <--> iMac cable! would require a small Setup intervention.

Maybe later.. re higher-speed modems; I'll be on Comcast's el-cheapo version for the duration (mine was to be a "6-months" trial)
but their bookkeeping indicates they won't bug me for a year; nice when corporate errs on My side.

Thanks for the al punte info, which I shall peruse ... as you say, the tradeoff of used price VS extra labor (basically the same as: buy Beastware+hardware cheaper and pay / and pay / in trouble time) -- suggests to me the above game.

PS -- another Corp bonus: turns out that the Tee Vee channels come down same pipe (well ... History , Comedy Central and a few other watchable sites.) So with a splitter I get the Intarweb and eye candy too.
No cable box to convert to recognizable 'channels', of course -- but between off-air and the freebies, n i c e.



Still and all ... Too Much ... Information.