Grateful Dead

Operator, can you help me, help me if you please.
Give me the right area code and the number that i need.
My rider left upon the midnight flyer,
Singin' like a summer breeze.
I think she's somewhere down south, down about baton rouge,
But i just can't remember no number, a number i can use.
Directory don't have it, central done forgot it,
I've gotta find a number to use.
Trying to check out her number, trying to run down her line.