Manoj,
The A3 is the antenna, what type of receiver are you using attached to the Recon? You should be using the R3 as this was sold as a bundle with the A3, R3, and Recon as a Post-Processed L1 survey solution.
If you can confirm that you are using the A3 receiver, then it is running NMEA which will work with ArcPad. Tell me, when you go to your GPS Preferences, have you clicked the "binoculars" icon to automatically look for the GPS? If everything is connected up hardware wise, it should locate the NMEA messages from the GPS Receiver.