Loss of Hi-Speed connection with Fax/Modem

I’m running Win XP Pro and have a Hi-speed, always on, internet connection with (Ethernet)cable modem. I also have dial up fax/modem(56K)installed to dial up to my company’s email. Whenever, I connect with my fax/modem(56K)I would loose my Hi-speed connection.

Any idea why and how can I stop this?

Thanks,

Wes