Question:
An MMF cash drawer will not open when it is connected directly to the serial port.

Answer:
To open most of these drawers, ANY two characters passed into the serial port will work. Some MMF units have a switch-selectable character to open the drawer. If the DIP switches on this type of drawer have not been adjusted, the default open character is a capital A. Cash drawers of the switch-able type from MMF have "ND" at the end of the model number.
To open 75% of all directly connected MMF cash drawers (especially the ECD232 series), try these codes in the devise cash drawer code:

1. Use a code of "1 65"

2. Use a code of "2 65 65"

This should open all MMF drawers requiring any one or two characters, and also any switch-able drawers that have not been modified.

More Information
MMF Cash Drawers, Inc. produces several different types of cash drawer interfaces for their products.