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MLS Delivery: Sort-to-Light

This guide introduces delivery at the Massachusetts Library System and provides all the necessary information about delivery, routes, scheduling, claim forms, etc.


For information and recommendations on using Sort to Light, please view our Best Practices for Sort-to-Light.

Using Routing Slips

When you don’t need to use a routing slip:

Items with barcodes on the upper left front of the book or upper left back of the book that were barcoded prior to 2009.

Please note: When placing items into the delivery bin, please ensure that the barcode is placed facing up.  If the barcode is on the back, then the book should be placed upside down in the delivery bin so the barcode is visible.

When you do need to use a routing slip:

All items with barcodes on the inside of the book.

Items being sent out via the Commonwealth catalog, even if the barcode is on the outside of the book.  These items will be sent back to your library if they do not have a routing slip. 

Items going to out-of-network libraries (for example, an MVLC item going to OCLN library always needs a slip). 

Items going to a ‘Certified Library’ should be treated like out of network material and labeled with a slip. 

How Does Sort-to-Light work?

Want to see how sort-to-light works?  Watch this short video featuring Optima's sort-to-light operations for the Massachusetts Library System.

What is Sort-to-Light?

Sort-to-light is a semi-automated sorting technology that allows libraries to ship materials without requiring a label to indicate the item’s destination.

Our studies indicate that elimination of this step shortens the time for processing an item for delivery at the circulation desk by one-third, i.e., a transaction with a label takes six seconds while a label-less transaction takes four seconds.

Sort-to-light technology is not new. It has been used for many years in other industries where it is also referred to as pick-to-light. This is the first implementation of sort-to-light technology in a library logistics setting.

In MLS’s case it works thus: an employee (sorter) at the contractor’s distribution center opens a tote full of unsorted materials shipped by a library. The sorter scans a barcode located on the front of the item with a wrist-worn scanner. The scanner polls the shared integrated library system (ILS) at a remote site via the Internet. The ILS responds with a SIP2 message which indicates the destination for that item (similar to a transaction with a self-check station). An LED light flashes to indicate to the sorter into which tote in the sorting rack to place the item. This technology allows for the separation of materials by other characteristics, e.g., items “on-hold” versus “returns.” The sort-to-light technology employed for MLS includes error detection to improve sorting accuracy.

To see how the sort-to-light process works, please view the video at the top of this page.

What is the External Barcode Policy?

The External Barcoding Policy established in 2009 requires items’ barcodes to be placed horizontally on the upper left corner of the front of the item. It is easier to place a barcode on an outgoing item once than it is to continually place a delivery slip in it for shipping. It is also helpful to circulation staff in all libraries because barcodes will be in a uniform location.

If the item pre-dates 2009 when the policy was set, you do not need to re-barcode items that have barcodes displayed horizontally on the upper left corner of the back cover. Items that have the barcode displayed vertically must be re-barcoded regardless of when the item went into circulation. When shipping, place these items “barcode up” in the tote. Items after 2009 must comply with the External Barcoding Policy, with barcodes displayed horizontally on the upper left corner of the front cover.

Items that have the barcode displayed vertically must be re-barcoded or a slip must be used regardless of when the item went into circulation.

If your library is not a member of a network, you do not have to follow the barcode policy.

Contact Information

Have a delivery question or concern? Contact Us!

Optima Customer Service:


MLS Delivery:

(508) 357-2121 option 1
(866) 627-7228


Label Less Shipping

MLS will work with networks and our Contractor to determine when a network is prepared to begin label-less shipping.  Eligibility criteria include: 

  1. All network members adhere to MSDC barcode placement policy for new items. 
  2. Network shipping attains an average of 75 percent external barcoding
  3. SIP2 (or mutally agreeable network/contractor communications protocol is successfully tested. 
  4. All items shipped without a properly placed external barcode shall be labeled.