How long can listen again on a panel record for?

From the ECS 525 manual ,



LISTEN AGAIN
The Listen Again facility will store up to fifteen seconds worth of audio as up to ten separate audio“messages”. The messages are accessed by pressing the auxiliary volume control to step back through the messages. Pressing and releasing the auxiliary volume control within 500ms will replay the first message. Pressing and releasing the  auxiliary volume control twice in 1 sec will step back to the second message, three presses in 1.5 sec will step back to the third message. When the control is used to step back to a message earlier that the last message all the subsequent messages are played with a beep between messages. When the last message in the playback is completed two longer beeps are output to signal the end of playback.Please update the labels!!!