Rings OK for me, but it's a slow beeeeeep beeeeeep beeeeeep ringing tone - I think that's an IP phone system.
If it IS a fax, you could always send a fax using a free trial from one of the online providers, or from your PC if you have a dial up model with fax capability installed:
Free trials available (Remember to cancel the subscription)
https://www.efax.co.uk/faxbyemail
http://www.myfax.co.uk/
https://www.hellofax.com/
XXXXX
October 2015