How to use Pattern to restrict data

Hi,

I'm developing an XML schema and I'm using "pattern" to restrict the valid
values for certain attributes.

One specific case is the phone number, I want to exclude telephone number
starting with 800, 888, 866, etc.  How should I do this?

I was using <pattern value="[0-9]{10}"/> so that only 10 digits will be
acceptable. But I cannot find a way to exclude those numbers.  
I looked on the web and cannot find a complete reference as how to use
"pattern" and what are the possible symbols can be used in the "value"
And what does each symbol mean.  (for example, I found some schema with "?"
in value which means optional, also there are schemas specify "*", "|", etc
in value but there are no explanation as what does each mean)

Can someone point me to a good reference with full explanation?

Thanks,

Sean