From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gordon JC Pearce Subject: RE: two way radio Date: Thu, 18 Nov 2010 18:54:51 +0000 Message-ID: <1290106491.21069.6.camel@localhost.localdomain> References: <20101118121549.GW2394@n0nb.us> <003b01cb873e$a8e96020$fabc2060$@no> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <003b01cb873e$a8e96020$fabc2060$@no> Sender: linux-hams-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" To: Robert Eliassen Cc: linux-hams@vger.kernel.org On Thu, 2010-11-18 at 17:35 +0100, Robert Eliassen wrote: > Eduardo, > > You still have to explain what your intentions are. Are you going to use the > FRS/GMRS-radio to transmit and receive data? > > PTT (Push To Talk) would be the trickiest part I guess. You may have to > modify the unit. > > Regards > Bob, LA6GHA Most of these wee cheapy radios have a stereo 2.5mm or 3.5mm jack socket with an earphone pin, a mike pin and ground. To put them into transmit, you connect a smallish resistor (typically 1k or so) across the electret mike element. The PTT circuit in the radio looks to see if you've pulled the mike line down - not totally to ground, but typically to about 1.5 to 3V - and switches to transmit. As other posters have said, there may be legal issues with using unlicensed radios for data comms. If you're controlling a remote PC, you may also find that you want to encrypt your traffic - except with an amateur licence you can't. Owing to the legal aspects, I can't recommend that you use these radios - if you get caught you could be in quite a lot of legal trouble, assuming your local equivalent of Ofcom aren't too busy catching pirate FM stations. Gordon MM0YEQ