Specifies the Service Message List Number to use on this
ALPS Circuit. This allows custom service messages to be sent
for ASCUs on a particular circuit. Service messages are sent out
by the router to the ASCU when abnormal conditions occur, and are
displayed on the terminal. There is a default set of service
messages, usually referred to as List 0. However, it is possible
to configure custom sets of service messages for display,
selectable on a per-circuit basis.