Love the black and white drawn rendering of this piece, it's very nostalgic and peaceful, however I'm not really into the concept (at least how it is presented now with the "hello" being a separate strand of wire that just stops instead of among the wire that reaches the house), and maybe have some kind of background to use the rest of the tee's space? Nice style tho, keep it up!
About my design
http://www.zws.de/unternehmen/kontakt/2008/02/20/dosentelefon_300breit_id3827311.jpg