Yes, great post (pointing at Navigator too). BTW, BriGuy, you might become a member at another discussion board, “Children with Diabetes”, because they seem to have many more parents using CGMS on children, and actively posting about it, than we have here. More parents, more and better advice.
The workaround for Dexcom is “the Radio Shack Solution”: Put a microphone next to the Receiver. (It can be a wireless or wired model; a cheaper “dynamic” type is more convenient because it doesn’t need to be powered.) Run the microphone into any stereo or boom-box with a microphone input, and turn on the stereo.
Wired microphones are often used with cables 30+ feet long (think of a big rock-and-roll stage), and you can buy 50 foot extender cables on eBay for less than $20.
There’s two issues, though, which might call for additional bits of equipment. First, those extra durable “professional-type” cables are a 3-pin design called XLR, while your stereo’s microphone input will be either 1/4" plug or mini-plug. (The plug is mono, not stereo; but two of the wires in the XLR are shorted, so it all matches up.) There are adapters for less than $5; eBay is again your friend. Often, when you buy a microphone with a detachable cable included in the box, it will already be XLR to 1/4" plug: So in that case, you’d merely use your extender cable first, from the microphone, and then plug the supplied cable between your stereo and the extender cable.
The other issue is this: These days, very few home stereos or boom-boxes have a microphone input; their only 1/4" jack is for headphones out, and their input jack is an “auxiliary”, used for iPods and similar portables. You’ll need either a microphone amplifier ($20-30 new), or an actual microphone mixer. (As little as $15 for a used piece of Radio Shack “Realistic” garbage, as I use; but don’t even look at professional-type mixers. They’re $$$$.) So put a search into eBay notifying you when someone has a mixer for sale, and put a maximum price of $20. Sooner or later, you’ll get an email about a matching item, and you’ll win one at the right price.
The cheap Realistic mixers have very noisy circuitry, not suitable for professional use. Even though it’s VASTLY better than children’s “spy toy” products, there is a constant hiss in my ear when I’m sleeping with one headphone earbud inserted. (I have been a Professional Musician in the past.) I use the earbud because I sleep much deeper than my wife: it’s connected to the mixer, with it’s own volume control, while my wife’s volume is set at the stereo system. So my earbud is LOUD, while the Stereo is only at moderate volume. Output from the mixer is RCA cable stereo at standard component volume/voltages. If you want the alarms to occur in multiple rooms, it’s fine to use “Y” adapters, or the “tape out” RCA jacks, to feed multiple stereos.
One last thing: You do not want to use an “omnidirectional” microphone for this purpose, it will pick up breathing noises. The pick-up pattern which you want your microphone to have is called “Cardioid”. IMO most “Unidirectional” microphones are a little bit too fucused for this purpose, when the Dexcom or Microphone move to be even slightly off-axis the sound level falls off too far. Cardioid is a slightly “wider” frontal pattern, that’s the one you want.