Here is an example from the FAQ noted below regarding using phone numbers.

If you wanted to your phone field to accept:

1-555-555-5555 or 555-555-5555 or 555-5555

Use: '\d{0,1}-?\d{0,3}-?\d{3}-\d{4}$'

Example:

'Telephone' => [10,'alpha',20,15,1,'','\d{0,1}-?\d{0,3}-?\d{3}-\d{4}$'],

If this does not provide the answer, please check the FAQ under the section "Syntax"

Unoffical DBMan FAQ
http://webmagic.hypermart.net/dbman/