two way radio

two way radio

[Eduardo]

Hi,

I have a pretty basic question. Is it possible to connect a two way
radio (like https://cobra.com/detail/microtalk-cxr925-35-mile-radio.cfm
) to a Linux box? Does anyone know a good reference explaining how to
make this connection?

Thanks in advance,
Eduardo

Re: two way radio

[Nate Bargmann]

* On 2010 18 Nov 05:09 -0600, Eduardo wrote:
> Hi,
> 
> I have a pretty basic question. Is it possible to connect a two way
> radio (like https://cobra.com/detail/microtalk-cxr925-35-mile-radio.cfm
> ) to a Linux box? Does anyone know a good reference explaining how to
> make this connection?

To do what?  As it is an FRS radio I doubt that anything but voice is
allowed, at least in the USA.  Outside the USA you may be able to use
data of some sort, depending on your local regulations.  To do that you
would likely connect the speaker/mic jack to the audio connections on a
sound card.  Looking at the specs I doubt there is any way to connect
the radio for frequency/channel selection.

73, de Nate >>

-- 

"The optimist proclaims that we live in the best of all
possible worlds.  The pessimist fears this is true."

Ham radio, Linux, bikes, and more: http://n0nb.us/index.html

Re: two way radio

[John Goerzen]

On 11/18/2010 05:07 AM, Eduardo wrote:
> Hi,
>
> I have a pretty basic question. Is it possible to connect a two way
> radio (like https://cobra.com/detail/microtalk-cxr925-35-mile-radio.cfm
> ) to a Linux box? Does anyone know a good reference explaining how to
> make this connection?

You'll need:

1) A way to get sound from the computer to the radio
2) A way to get sound from the radio to the computer
3) A way to key PTT from the computer.

#1 and #2 may be solved easily if it has headphone and mic jacks.  #3 
may be more complicated, though you may be able to use VOX.  The precise 
circuits needed vary by radio.

-- John

Re: two way radio

[Eduardo]

Hi Nate / John,

Thanks for your replay.

What (cheap) radio would you recommend to transmit data? Could you
also point a place where I can find the circuit needed to connect this
radio to a Linux box?

Best regards,
Eduardo

On Thu, Nov 18, 2010 at 10:15 AM, Nate Bargmann <n0nb@n0nb.us> wrote:
> * On 2010 18 Nov 05:09 -0600, Eduardo wrote:
>> Hi,
>>
>> I have a pretty basic question. Is it possible to connect a two way
>> radio (like https://cobra.com/detail/microtalk-cxr925-35-mile-radio.cfm
>> ) to a Linux box? Does anyone know a good reference explaining how to
>> make this connection?
>
> To do what?  As it is an FRS radio I doubt that anything but voice is
> allowed, at least in the USA.  Outside the USA you may be able to use
> data of some sort, depending on your local regulations.  To do that you
> would likely connect the speaker/mic jack to the audio connections on a
> sound card.  Looking at the specs I doubt there is any way to connect
> the radio for frequency/channel selection.
>
> 73, de Nate >>
>
> --
>
> "The optimist proclaims that we live in the best of all
> possible worlds.  The pessimist fears this is true."
>
> Ham radio, Linux, bikes, and more: http://n0nb.us/index.html
> --
> To unsubscribe from this list: send the line "unsubscribe linux-hams" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>
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Re: two way radio

[Dave Platt]

>> I have a pretty basic question. Is it possible to connect a two way
>> radio (like https://cobra.com/detail/microtalk-cxr925-35-mile-radio.cfm
>> ) to a Linux box? Does anyone know a good reference explaining how to
>> make this connection?
> 
> You'll need:
> 
> 1) A way to get sound from the computer to the radio
> 2) A way to get sound from the radio to the computer
> 3) A way to key PTT from the computer.
> 
> #1 and #2 may be solved easily if it has headphone and mic jacks.  #3 may be more complicated, though you may be able to use VOX.  The precise circuits needed vary by radio.

Here in the U.S. you have to be careful in what you do along these
lines due to the FCC regulations which govern FRS radio use.

-  You may not make any internal mofifications of the radio at all.
-  You may not interconnect to the telephone network
-  Voice use only, with very limited exceptions for very specific forms of
   data transmission
-  Two-way person to person communications only, again with limited
   exceptions.  No one-way (broadcasting) allowed.
 
Within those limitations, though, is is as you say.  A radio prewired with a
jack or jacks for an external speaker-mike with PTT switch or VOX would
be a good choice, as it would not require internal modifications to be
hooked up to a PC sound interface via e.g. a Buxcomm RASCAL or
similar devicr (isolation transformers, pad resistors, and a PTT drive
circuit, all easy to homebrew).

RE: two way radio

[Robert Eliassen]

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

-----Original Message-----
From: linux-hams-owner@vger.kernel.org
[mailto:linux-hams-owner@vger.kernel.org] On Behalf Of Eduardo
Sent: 18. november 2010 15:51
To: linux-hams@vger.kernel.org
Subject: Re: two way radio

Hi Nate / John,

Thanks for your replay.

What (cheap) radio would you recommend to transmit data? Could you
also point a place where I can find the circuit needed to connect this
radio to a Linux box?

Best regards,
Eduardo

On Thu, Nov 18, 2010 at 10:15 AM, Nate Bargmann <n0nb@n0nb.us> wrote:
> * On 2010 18 Nov 05:09 -0600, Eduardo wrote:
>> Hi,
>>
>> I have a pretty basic question. Is it possible to connect a two way
>> radio (like https://cobra.com/detail/microtalk-cxr925-35-mile-radio.cfm
>> ) to a Linux box? Does anyone know a good reference explaining how to
>> make this connection?
>
> To do what?  As it is an FRS radio I doubt that anything but voice is
> allowed, at least in the USA.  Outside the USA you may be able to use
> data of some sort, depending on your local regulations.  To do that you
> would likely connect the speaker/mic jack to the audio connections on a
> sound card.  Looking at the specs I doubt there is any way to connect
> the radio for frequency/channel selection.
>
> 73, de Nate >>
>
> --
>
> "The optimist proclaims that we live in the best of all
> possible worlds.  The pessimist fears this is true."
>
> Ham radio, Linux, bikes, and more: http://n0nb.us/index.html
> --
> To unsubscribe from this list: send the line "unsubscribe linux-hams" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>
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Re: two way radio

[Eduardo]

Hello Robert,

I want to send commands (and receive status) to a Linux box. I am not
quite sure what band I can use. I am in Brazil and I think (I'm not
completely sure) that I can use CB here for that.

Regards,
Eduardo

On Thu, Nov 18, 2010 at 2:35 PM, Robert Eliassen <robel@vktv.no> 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
>
> -----Original Message-----
> From: linux-hams-owner@vger.kernel.org
> [mailto:linux-hams-owner@vger.kernel.org] On Behalf Of Eduardo
> Sent: 18. november 2010 15:51
> To: linux-hams@vger.kernel.org
> Subject: Re: two way radio
>
> Hi Nate / John,
>
> Thanks for your replay.
>
> What (cheap) radio would you recommend to transmit data? Could you
> also point a place where I can find the circuit needed to connect this
> radio to a Linux box?
>
> Best regards,
> Eduardo
>
> On Thu, Nov 18, 2010 at 10:15 AM, Nate Bargmann <n0nb@n0nb.us> wrote:
>> * On 2010 18 Nov 05:09 -0600, Eduardo wrote:
>>> Hi,
>>>
>>> I have a pretty basic question. Is it possible to connect a two way
>>> radio (like https://cobra.com/detail/microtalk-cxr925-35-mile-radio.cfm
>>> ) to a Linux box? Does anyone know a good reference explaining how to
>>> make this connection?
>>
>> To do what?  As it is an FRS radio I doubt that anything but voice is
>> allowed, at least in the USA.  Outside the USA you may be able to use
>> data of some sort, depending on your local regulations.  To do that you
>> would likely connect the speaker/mic jack to the audio connections on a
>> sound card.  Looking at the specs I doubt there is any way to connect
>> the radio for frequency/channel selection.
>>
>> 73, de Nate >>
>>
>> --
>>
>> "The optimist proclaims that we live in the best of all
>> possible worlds.  The pessimist fears this is true."
>>
>> Ham radio, Linux, bikes, and more: http://n0nb.us/index.html
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-hams" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>
> --
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> the body of a message to majordomo@vger.kernel.org
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>
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RE: two way radio

[Gordon JC Pearce]

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

RE: two way radio

[Robert Eliassen]

Ah, so you're like going to telnet into a Linux box via radio! 

Ok, so the clue here is "I want to control my Linux box 20 miles away, and
there is no other way but via radio". 

The good news is that dual-mode GMRS/FRS equipment is approved in Brazil
according to http://en.wikipedia.org/wiki/Family_Radio_Service

When it comes to legal modifications and the legal use of data communication
you should Google (in you language) for answers.

Assuming it's legal, the rest is pretty straight forward. You can check out
http://www.faqs.org/docs/Linux-HOWTO/AX25-HOWTO.html although it's pretty
old. 

73
Bob, LA6GHA

-----Original Message-----
From: linux-hams-owner@vger.kernel.org
[mailto:linux-hams-owner@vger.kernel.org] On Behalf Of Eduardo
Sent: 18. november 2010 18:31
To: Robert Eliassen
Cc: linux-hams@vger.kernel.org
Subject: Re: two way radio

Hello Robert,

I want to send commands (and receive status) to a Linux box. I am not
quite sure what band I can use. I am in Brazil and I think (I'm not
completely sure) that I can use CB here for that.

Regards,
Eduardo

On Thu, Nov 18, 2010 at 2:35 PM, Robert Eliassen <robel@vktv.no> 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
>
> -----Original Message-----
> From: linux-hams-owner@vger.kernel.org
> [mailto:linux-hams-owner@vger.kernel.org] On Behalf Of Eduardo
> Sent: 18. november 2010 15:51
> To: linux-hams@vger.kernel.org
> Subject: Re: two way radio
>
> Hi Nate / John,
>
> Thanks for your replay.
>
> What (cheap) radio would you recommend to transmit data? Could you
> also point a place where I can find the circuit needed to connect this
> radio to a Linux box?
>
> Best regards,
> Eduardo
>
> On Thu, Nov 18, 2010 at 10:15 AM, Nate Bargmann <n0nb@n0nb.us> wrote:
>> * On 2010 18 Nov 05:09 -0600, Eduardo wrote:
>>> Hi,
>>>
>>> I have a pretty basic question. Is it possible to connect a two way
>>> radio (like https://cobra.com/detail/microtalk-cxr925-35-mile-radio.cfm
>>> ) to a Linux box? Does anyone know a good reference explaining how to
>>> make this connection?
>>
>> To do what?  As it is an FRS radio I doubt that anything but voice is
>> allowed, at least in the USA.  Outside the USA you may be able to use
>> data of some sort, depending on your local regulations.  To do that you
>> would likely connect the speaker/mic jack to the audio connections on a
>> sound card.  Looking at the specs I doubt there is any way to connect
>> the radio for frequency/channel selection.
>>
>> 73, de Nate >>
>>
>> --
>>
>> "The optimist proclaims that we live in the best of all
>> possible worlds.  The pessimist fears this is true."
>>
>> Ham radio, Linux, bikes, and more: http://n0nb.us/index.html
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-hams" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>
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