Determining what ML TYP 'Class of Mail', 'Mail Type', and 'Presort Type' a mailpiece is in MailStream Plus

Product Affected:  MailStream Plus™
The USPS DMM (Domestic Mail Manual) gives all of the information.  The details are too much to go into in a Knowledge Base article.  For assistance, your USPS Clerk can also provide information about determining the Class of Mail, Mail Type, and Presort Type. 

Very briefly-
1) First it must be determined what class of mail your mailpiece is.  For example, some mail is *required* to be First-Class.  Or to qualify as a Periodicals mailing, certain requirements must be met.

2) Then you determine what Mail Type you have.  Does the mail piece physically qualify as a letter?  Or does it have to be a Flat, or a Parcel, etc.

3) Lastly, there are particulars about the Presort Type, and what MailStream Plus (MSP) supports.  For example, in First-Class, MSP supports "Regular" and  'Priority Mail', or for Package Services, MSP supports Bound Printed Matter, and Special (Media Mail® or Library Mail.)

This information is used on the ML TYP parameter (and in some cases also on the P ATTR parameter), to tell MailStream Plus what type of mailing it is.  

Note: further information about the mail piece is input using other parameters, like the P ATTR, ALG BC, etc.  Such as whether the mail pieces are physically automation-compatible per the USPS regulations for the type of mailing, and will the mail pieces be getting barcodes on them.

Information about MSP parameters are in the MailStream Plus Reference Guide, available on the website. 
UPDATED:  November 8, 2018