Suitable interface for palio & Linea

[Navin Talati]

Friends,
I need your help for getting information of the car data.

As I understand, for this an ECU scaning is required. There are On-Board Diagnostc Ports in all ecu based cars. This port is connected to a computer/mobile/tablet etc via some INTERFACE device. Software installed in the system (i.e. computerr/mobile/tablet etc) exhibits all relavent data and graphs etc. on the screen.
I feel this practice is more preferred to find a fault in the car. This way we can prvent any technician doing experiment on trial and error basis. Some times this type of his practice may more seriously damage to our vehicle. And it is but natiural that such person could not be expected with up-to-date circuitary/chip level electronics knowledge. This is even almost impossible at Fiat Authorised Service Centers spread all over the country ! (may be a rare exemption).
I understand this linkage flow as under:

Car's OBD Port <----------> INTERFACE DEVICE <--------> SOFTWARE

USB or BlueTooth Type Installed in Computer



As per this understanding of mine, I request you all to guide me for the following:

(A). Where is the location of OBD ports in
(1) Fiat Palio 1.2 nv petrol dec.2004 Model (Indian Version)
(2) Fiat New Linea T-Jet 1.2 Petrol March-2014 Model (Launched in India - 2014 version)

(B). Which Specific Interface Device should I buy for each vehicl? Is a common device
available?
(C). Which best Software is available for each. Is any FREE software available?

Please, try to give detailed answer as far as possible.
A prompt and positive response is eagerly awaited.