What is a JR module ?

Many radio models have the final "transmission" piece as a separate, removable/replaceable unit (ie module).  This allows for the same radio to use different frequency bands, signal encoding schemes etc just by changing to different modules. 

A JR module is such a module.  So if you have a Futaba radio that supports modules, you may be able to find a "JR module" designed for Futaba radios so that you can use JR receivers, instead of Futaba receivers.  Or you can go from 72Mhz to 2.4Ghz on a JR radio, by using the appropriate "JR module".

Any idea if Futaba to Jr Module available 2. 4 gz. For Futaba 12 z radio.

In any Proportion control Radio, there is basically
1. Mechanical joystick part with POTs (Variable resister).
2. Electronics to generate multiplexed waveshape that have the continuously single line serial like data that can control servo/ESC etc in PPM/PCM with mixing/servo reversing basic feature or/and micro-controller controlled mixing feature.
3. Radio transmitter module that transmit the PPM/PCM Data with various radio technique (even with feedback too).
4. Antenna (depending upon Radio transmitter block).

Inside Receiver
============
1. There is basically a Radio receiver depending upon the transmitter that regenerate audio PPM/PCM Data.
2. Demultiplexer that gives continuous serial single line data to multi line individual data.

Now, In Transmitter (Truely speaking Proportion control Transmitter) sl. no. 3 No 4 are made custom aling with complete receiver block which makes advancements of the communication system and the radio communication frequency can be controlled depending upon rules and regulations of different country keeping the rest same.

So, here comes the idea of module, that adds communication advancements only with range too having only transmitter and antenna portion along with receiver.

JR is a standard ? or a company ?. flysky FS-TH9X , 9 channel transmittter also has a radio module is this JR ?
http://rcbazaar.com/products/397-fs-th9x-9ch-24ghz-transmitter-receiver.aspx

JR is one of the leading company in Radio industry.
http://www.jrradios.com/

JR is a company which makes transmitters, receivers, servos etc.
Flysky is also a company which makes transmitters, receivers. The above mentioned radio comes with flysky module.
But if you want to use JR receivers with Flysky transmitter then you can replace flysky module with JR module.

Futaba 12Z and 14MZs use the same modules, so this one should be compatible.  I have a spare one, in case you want it (bought for making an iPhly transmitter, but changed plans to use the FrSky one instead).

http://www.espritmodel.com/spektrum-dsm2-24ghz-air-module-futaba-mz-dm9.aspx

does this require any hardware changes or its plug and use ? i want to do it to get extended range is there a way ?

If you are using JR module then i guess you have to do some modifications.
Here are some threads on RCG about this

http://www.rcgroups.com/forums/showthread.php?t=1231700
http://www.rcgroups.com/forums/showthread.php?t=1475742

If you are using JR compatible modules then no mod should be required. ( modules which can be used with JR receivers but are made by corona, Assan and not by JR)

http://helifreak.com/showpost.php?s=33874e72615011ba12b620dbb422d847&p=1819571&postcount=6

For long Range JR compatible module
http://diydrones.com/profiles/blogs/new-uhf-jr-module-for-turnigy?xg_source=activity


btw how much long range do you need?

Right now i have this radio FS-TH9x (came with a 8 channel flysky receiver).
http://www.flysky-cn.com/eShowProducts.asp?id=43

I think its JR  compatible. The FrSky JR module (DJT 2 way module) looks like it fits in the back of this radio  they have the same pinout. (But it will be good if someone confirms it). (max range of 2.5 kms is disappointing but if no other go, then, i'll have to use the same)

@spitfire
Range, well i'll be happy with 4-5 kms   i want to do FPV and i'm happy with 4-5 kms range. I'm new to this and i hope this should be sufficient. What do you think ? and i want to do fpv on a heli  

As you want to do FPV, you can follow this thread.
http://www.rcindia.org/self-designed-diy-and-college-projects/feiyutech-fy21ap-ap117(osd)-autopilot-and-stabalization-system/

Also search on this forum, google and RCgroups. you will find lot more information.