ISDN Signaling
Field
Integer multiples of 5, in the range 5000 through 20000
10000
Specifies the value of the T203 timer, which acts as a handshake mechanism when ISDN L2 is in Multiframe Established state or Active state. If the timer expires, an L2 message is sent to the switch to ensure that it is still active. If no response is received, L2 comes out of the active state and tries to restart the L2 trunk.