The AEC system has more than 4 doors, but only readers 1 through 4 will work. In addition, the relays for any reader after number 4 stays constantly activated.
By default, the AEC programming comes with only readers 1 through 4 in the locked position. All other readers are programmed for "Unlock door." When the door is in an unlocked state, the associated reader will not read cards or generate any card transactions. The relay for unlocked readers will also remain in an activated state.
To resolve this issue, log into the AEC programming and browse to Card Readers. Then select your reader. Select the Reader Options link, and chose any other Scheduling Option other than Unlock Door. Save your settings and test.