Note that to be a CDS member you must also be an NSS member.
Download and print PDF Form then Join or Renew by Mail or Fax
Download and complete the application/renewal form. Mail or fax with payment to the address shown in the left column (you can also scan the completed form, save it as a PDF and send via e-mail).
Using the printed form may be preferable if you have a more complex application or renewal (i.e., family and/or lifetime memberships, already an NSS member, etc.)