The pin connector is shown in the picture:

tip - power +5V;

ring - signal;

base - ground;

Connector - 2.5 mm stereo jack.

As a photodetector you can use any integrated receiver for 38KHz with 5V power supply.

For example:

TSOP31438 http://www.vishay.com/docs/82492/tsop312.pdf

TSOP58438 http://www.vishay.com/docs/82461/tsop582.pdf

With high probability the receiver can be the same as computer TV tuner - they quite often have the same type of connector and pinout.

It is recommended to install capacitor 1-10mcF near receiver for improving power supplies immunity.