I stripped the end of the cable, and it's definitely coax. The cable does have some markings on it, but none of them show a manufacturer name. Here's exactly what it says along the cable:
KV2908111 9900963 BMU (ETL)us 14 AWG "150V" (phone symbol)
Where (phone symbol) is a little picture of a telephone handset in a horizontal position. (I took a picture of it, but I don't know how to add it to this post.) This little phone symbol is the thing that makes me think that this must be the right cable, only I've never heard of coax phone cable before.
