[Asterisk-Users] Re: FRS over *
heya David ( Josephson ) :) Only one brand of cheap GMRS radios that I've seen (Garmin) has the duplex mode that allows use with repeaters and duplex base stations. I think this is essential for successful integration with a phone system. so i check 2-way radio on the garmin site http://www.garmin.com/outdoor/products.html#2-way http://www.garmin.com/products/rino/ http://www.garmin.com/products/rino120 http://www.garmin.com/products/rino130 I phones tech support they claim in gmrs mode and frs mode these radio are not duplex... did you have some more info here is thre some other garmin product you are using ? ___ Asterisk-Users mailing list Asterisk-Users@lists.digium.com http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
Re: [Asterisk-Users] Re: FRS over *
I haven't seen any duplex handhelds that I can remember (ther must be some). The repeater would most likely be duplex. Many repeaters are built from either two under-dash mobile radios or the old GE MasterII units The question you really want to ask is if they can operate on different transmit and receive frequencies. This is normally referred to as semi-duplex. http://www.shipmanenterprises.com/freetalk-xl.htm http://www.antennasystems.com/midland_radio.html I've looked at the dingotel 446 stuff. Looks like you just need a handheld with a good VOX. And, since GMRS regs allow wireline control, I suppose that as long as you never got to the PSTN, you would be ok. Read the regs and decide for yourself. James Taylor On Tue, 01 Mar 2005 09:52:37 -0800, TC [EMAIL PROTECTED] wrote: heya David ( Josephson ) :) Only one brand of cheap GMRS radios that I've seen (Garmin) has the duplex mode that allows use with repeaters and duplex base stations. I think this is essential for successful integration with a phone system. so i check 2-way radio on the garmin site http://www.garmin.com/outdoor/products.html#2-way http://www.garmin.com/products/rino/ http://www.garmin.com/products/rino120 http://www.garmin.com/products/rino130 I phones tech support they claim in gmrs mode and frs mode these radio are not duplex... did you have some more info here is thre some other garmin product you are using ? ___ Asterisk-Users mailing list Asterisk-Users@lists.digium.com http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users -- James Taylor 3505 Summerhll Road Suite 11 Texarkana, Texas 75503 903-793-1953 ___ Asterisk-Users mailing list Asterisk-Users@lists.digium.com http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
[Asterisk-Users] Re: FRS over *
On the various technical issues raised here (OK, we posted the rules, we won't discuss the legality anymore) I think there is only one main obstacle to using FRS radios for extensions on *. They are simplex (push-to-talk, release-to-listen). The protocol for dealing with voice-activated-switching (VOX) has been used in ham and public safety simplex autopatches but it's really tricky to get right. It would be much easier if you used GMRS or business band radios programmed to transmit on one frequency and listen on another, that way the base can be set up with one pair of frequencies and the portables on the opposite split. Yes, you need two antennas or a duplexer, but this would be a better way to do it than trying VOX and carrier interruptions to make it work simplex. Some of the cheap FRS radios have surprisingly good RF performance, I wouldn't be too put off by hams telling you they will self-destruct. Yes, they are programmed to time out after a few seconds or a minute of talking, but you will need to make your transmissions brief anyway so you can hear what the other people on the channel are saying. They aren't as fragile as they look. FRS is also narrow band (3 kHz deviation, 11.25 kHz channel bandwidth). I don't think you would be able to get more than about 1200 bps of data over this channel. Garmin does transmit GPS data over GMRS at that rate. The modern (last 10 years or more) commercial Motorola radios don't need a special programmer, just an interface box and PC software (which can be expensive). But only a few of these have the narrow band mode needed for compatibility with FRS (and none are legal for FRS as they are not type-accepted as such). Nearly all are OK for GMRS though. These were very expensive radios though, and while you might get them on eBay for $10, the batteries will be much more than that. Only one brand of cheap GMRS radios that I've seen (Garmin) has the duplex mode that allows use with repeaters and duplex base stations. I think this is essential for successful integration with a phone system. My recommendation would be to use a duplex base station radio on a low power business band channel pair. Any of the low power UHF repeaters would be OK for this (the repeater logic is all handled by app_rpt). You can get a license for the itinerant frequencies that costs just a little more than a GMRS license, and be able to use real portable and mobile radios and real antennas. There are plenty of these available with dtmf pads so you could have full control of your * switch. ___ Asterisk-Users mailing list Asterisk-Users@lists.digium.com http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
