Hi All,
I've seen these DTR (or DTS?) digital radios on the 'bay. Look like they may be built on an iDEN chassis, with the speaker grille design of an XTS, but a little larger than a well built FRS rig. Few quick questions...
*Are they iDEN based? If so, has anyone "played" with these. Has anyone found any "uses".
*I see in photos/descriptions "public groups". Is this some sort of digital 900mhz equivalent of MURS/DOT/Star channels? Noticed a lot of retail/businesses using these, and wondering if these are monitorable.
*I think everbody (us) keeps some DOT/STAR/MURS radios around for license-free monitoring, and wondering if this is something that some of us should think of adding to our "arsenals".
I poked around a little, still havn't found any "white papers" or specs on these. (iDEN/Spread Spectrum/TDMA???)
Rich
Take a look at an i355 NEXTEL phone. It uses all the same accessories and battery that the DTR portables use. I suspect the DTR portables share a common hardware design with some iDEN portables.
The FHSS system appears to be identical to NEXTEL's off-network DirectTalk (DT) feature that some phones have. This is NOT the same thing as and not to be confused with the normal 2-way DirectConnect feture thru the iDEN network. The off-netowrk DT feature appears to be identical to what the DTR system uses. This is why my girlfriend and I kept our Motorola i355 NEXTEL phones even though we're not NEXTEL customers any more.
We've used them like FRS on a few occasions and they work as advertised. Audio quality excellent. The digital audio delay between talking into one phone and hearing it out the other phone is close to a full second. Useable range appears to be similar to FRS. My g/f and I have used them while shopping at WAL*MART where NEXTEL coverage was nonexistent inside the store. The DT feature worked really well for us while inside the store because we're talking directly to each other on 900MHz and not on the NEXTEL network.
My g/f and I have used our phone's DT feature while at a concert. Security was tight (no cameras or recording devices, etc.) but cell phones were OK (didn't seem to care about cell phones w/camera). I was worried about us trying to bring in 2-way radios to use but we solved that with our NEXTEL phones and used them in DT mode.
One thing mentioned in the phone documentation is that the DT feature is NOT private. It can be heard on any other NEXTEL phone having the same DT feature and obviously can't be heard on scanners. I've monitored other DT users on occasion with my iDEN phone in DT mode. Think of it as a "public" talkgroup, just like using a conventional analog 2-way radio ("dot" channels, etc.). There is also a "private" mode where some form of encryption might be used (dunno for sure) and you have to enter the full area code and number of the other phone you want to talk to. I suspect the phone number in each other's phone is used as an encryption key for communication in each direction. In "private" mode, it is clamed to be as secure as the iDEN network.
While NEXTEL phones with the off-network DirectTalk feature may use the same FHSS system at the DTR portables, I suspect they are purposely coded differently so they can't intercommunicate. It would be cool and VERY useful if an iDEN phone operating in off-network DirectTalk mode could communicate with a DTR portable. Has anybody tried this yet or have any more information?
