I bought one infra-red receiver. It had three pins said pin 1, 2 & 3. The pin 2 connected to a metal case. I didn't know how to connect it with suitable voltage in order to make it to work properly. I tried to use multi-meter to check it polarity. It seemed forward bias when connected +V to pin 2 and 0 to pin 1 and the back of this receiver wrote the following words:

1 Z

0 0 2 3

The side view should be:

_|
(x|
-|
|
|

The front view should be:

_____
|(x)|
| |
-----
| | |
| | | (x : outward)
3 2 1