satellite comunications between each other

Hi
I want to get some information about how 2 or more satellite out of atmosphere can communicate. please have attention not to communicate with the Rx or Tx in earth, but 2 satellite around the ground. Can anybody help?

do a google search on the TDRS satellites (Tracking Data and Relay Satellites) that NASA and co use, They are all linked

Dave

Thanks alot Dave
this is a particular satellite that Nasa Use and good for my report ,but i want to know that any other satellite in the space have this utility to communicate each other? and if they have, how do this in which frequency band?

inter-satellite usually use laser telecommunications. The laser telecommunications always have at least two laser beam, the wider beamwidth for tracking, and the narrow one for telecomms.
The frequency band is selected specially, which has little attenuations out of atmosphere, but greatly attenuated by atmosphere, that is for security cuase.