timestamp with time zone, retrieving input offset/timezone

Hello there,

We are creating an Application that needs to handle timestamps in different timezones in particular:

Input and output in timezone of the User is no problem with

Set Time Zone and At Time Zone

But know I have two Users A and B in different  timezones.

When A saves a timestamp I want B to:

-          Get the timestamp displayed in his timezone

-          Get the timestamp displayed in the timezone a originally saved it in

Does the type “timestamp with time zone” contain the original timezone or at least the offset to UTC it was saved in, or does it just save the UTC time?

If it saves the timezone/offset, how can I access it?

Regards,

Der Tung