Optional information lines include the optional endorsement line (OEL), carrier route information line, ACS participant code, and mailer’s keyline. The OEL and the carrier route information line may be printed on the mailpiece or label when the address is printed. A mailer’s keyline is reserved for the mailer’s use except where required by the USPS.
Optional Endorsement Line (203.7.0)
Mailers may prepare mailings without applying pressure-sensitive labels or facing slips to the top mailpiece of bundles, except each mailpiece in a FSS bundle must bear an OEL in human-readable text as described in 184.108.40.206, by using a specific OEL above the address block or on the address label on the top mailpiece of a bundle.
Type and style:
ZIP Code: Except for carrier route bundles, the OEL must include the appropriate ZIP Code information (see 220.127.116.11).
Address Change Service (507.4.2)
Mailers receiving address corrections through Address Change Service (ACS) may use the first eight positions on the left side of the OEL for the ACS participant code. ACS codes must be printed in a non-narrow variant of Helvetica or Arial sans serif fonts in a range of 10 to 12 points (see Publication 8A, Address Change Service - Traditional, or Publication 8B, One Code ACS Technical Guide for details).
Carrier Route Information (203.8.0)
Bundles made up to individual carrier routes, rural routes, highway contract routes, Post Office box sections, or general delivery units may be prepared without a facing slip if the standards in 203.8.1 are met. These standards apply to carrier route Periodicals, Enhanced Carrier Route USPS Marketing Mail, and carrier route Bound Printed Matter mailings. For preparation of facing slips, see 203.4.1.
Placement and format:
Carrier route information consisting of a descriptive prefix (or its abbreviation), plus a route number or numeric code, must be on the top line of the address, either alone or with other optional information. A minimum of 10 spaces must be allowed for carrier route information when included with other information on the OEL. Carrier route information must be preceded by at least two asterisks (**). The carrier route information is in addition to the marking standards for the class of mail and price claimed.
A mailer’s internal keyline or comparable information may not be placed above or on the same line as the OEL. Authorized Manifest Mailing System mailers must use a keyline as described in 705.2.3.
1. Mailer must include the appropriate 3-digit ZIP Code prefix or 5-digit ZIP Code required by the labeling list for the mail class as shown in 203.7.1.
2. Pieces with this marking must meet the standards in 18.104.22.168. Use “C” for carrier route, “G” for general delivery, “H” for highway contract route, “B” for Post Office box section, or “R” for rural route followed by the route number or numeric code.