(only sysop, init.bcm)
Syntax: MAILBEACON [ 0 | 1 ]
(default: 0)

If the value of MAILBEACON is set to "1", a mailbeacon (file "beachead.bcm")
is send each time. If set to "0", a beacon is only send, if new usermails
are available in the mailbox.

The default value is "0" and must not changed until the sysop wants this
special feature enabled.