Oscar v12 has a feature to check the status from the Admin menu. Admin, Misc, Fax Status
If that doesn’t work, or if you want to do it manually, here is the procedure:
1) start putty
2) login to server
3) check status: sudo faxstat
If you do not see the message from step 5), continue to 4)
If the server is Running and idle, then the problem is not the server.
4) restart hylafax: sudo service hylafax restart
5) check status: sudo faxstat
Server should answer: HylafaFAX scheduler on servername: Running
Modem ttyUSB0 (+1.514.555.1234): Running and idle
6) exit