Broadband and fax on same line with Eircom

I have a basic business broadband package with Eircom. As I understand it, this means that I have to incur the cost of renting a telephone line (which I do). My fax machine is also connected to this phone line. I have just realised that my internet access is cut off while sending and receiving faxes (I had thought it was just a bad, frequently down broadband service, but finally aligned cause and effect). The internet connection is shared by 5 users on my office network. The regular interruption of internet access is a needless irritation. I have two questions:

1. Is it normal\inevitable that the fax would interrupt the internet access, or is there some setting or connection which could be adjusted?

2. If this is normal, what would be the cheapest fix or cheapest alternative to avoid this problem? I currently pay for 2x ISDN (i.e. four lines) for telephony, plus one separate line (for broadband and fax).

I have a telephone guy, but I would like to get some views before calling him. I half suspect that my current setup is not the best value option, but maybe I am being unfair on my supplier.

I have my office networked on the Microsoft Small Business Server bundle, and I know it is possible to set the server up to send and receive faxes, but I prefer not to, as it is important to me to print a fax confirmation sheet and place it on the relevant paper file each time a fax is sent.

Broadband and normal voice or fax use of the line should coexist as long as you have microfilters installed at all relevant points. Do you? Broadband cutting off while the fax or telephone is in use sounds suspiciously like a missing microfilter issue.

Apart from that is a single voice/fax line shared by all employees sufficient for your needs of will you need to expand on this sooner rather than later? Could you benefit from using VoIP over your broadband connection for voice calls?

95% of the time is going to be your filters , but some fax machines are incompatible with broadband (usually the top of the range ones).....

Thank you both;
I will look into this and let you know if this resolves the problem.

you might also be interested in checking out efax.com this will allow you to send a fax through your computer and not effect your line also you computer may already have a winfax(or something similar) installed which will let you do the same thing with no monthly fee.