I'm not sure the purpose for a US-Iran hotline Ray.  In the cold war it was to help ensure immediate unfiltered/unvetted (but translated) communication (teletype, not voice, if I am not mistaken) between both nation's leaders who were responsible for deciding if that nation was going to war.  Ostensibly both nations leaders did not want to go to war.

There was also parity (at least perceived) of a sorts (mutually assured destruction).

The Iranians pose zero serious threat to the nation as a whole.  Iran can be a thorn in the plans of our rulers, and can even kill some of them, but the US can wipe them off of the face of the planet in under an hour if it wanted to (and was willing to absorb the consequences of its actions).   

Also, clearly the rulers of the USA have been working towards 100% domination of every nation in the Middle East for at least a couple of decades.  The Neocon-Petroleum-Christian-MIC chickenhawk factions have been winning the never ending cycle of war in the region.  And they are closing in on the final boogeyman standing in their way:  Iran.  Who opposed the leaders chosen for them by the West since Mosaddegh or arguably even at the beginning of the 20th Century.

What is the point of a hotline...to send a clear ultimatum.  I am pretty sure that message has already been delivered and is well understood.  There shall be no peace so long as the US government rules.