Jul 10, 2015
If they are using a faxmodem card in a computer to send these calls, all that will happen is a little bit of hard drive space will be used. It would take tens of thousands of pages to use up a significant amount of hard drive space.
Sending those blank-page faxes does not take up a lot of phone time due to data compression - any single-color page is a very small amount of data.
For more information :
https://en.wikipedia.org/wiki/Black_fax