USPS Mail USPS mail service is for agencies inside of Wake County with a MSC number and is used for mail going outside of state government. The MSC presorts all outgoing USPS mail when possible to obtain the maximum discount from the Postal Service, saving state government millions of dollars annually. When addressing USPS mail, please be sure you have your return address with MSC number, city, state and zip listed in the upper left hand corner of the letter or package. Please list the recipient’s information in a larger font, in the center of the envelope or package. USPS mail is billed through the NCAS system and hits the department’s cash management the second week of each month for the prior month’s services. A copy of the billing is emailed to each department. Presort Services For information on Presort services, please contact Jorham Diaz at email@example.com or 919-733-2913.