How many pins in the connector? 2-4 would be phone. Ethernet is usually 8, but seen a rare few with 6 (PC to PC). Just look for how many gold colored connectors on the ends. Fanned and Watching :)
its part of a home alarm it gos with ag block and that is the cord it plugs into 2 ag or hg blocks.i hope tjis helps.i cant give any more info or ill be in trouble with alarm co every were.