It's impossible create hotline for off hook phone , it's possible create a virtual hotline when phone make first digit ,( create a specific Table in dialplan and assign the phone in this dialplan ) , see dialplan:
Table Create 4 Hotline
/ Id Entry Digits Min Max Class Prio Route
/ -- ----- ------------ --- --- ------------- ---- -----
TableEntry Create 1 1 1 1 1 Internal 0 10
TableEntry Create 1 2 2 1 1 Internal 0 10
TableEntry Create 1 3 3 1 1 Internal 0 10
TableEntry Create 1 4 4 1 1 Internal 0 10
TableEntry Create 1 5 5 1 1 Internal 0 10
TableEntry Create 1 7 6 1 1 Internal 0 10
TableEntry Create 1 8 7 1 1 Internal 0 10
TableEntry Create 1 9 8 1 1 Internal 0 10
TableEntry Create 1 12 9 1 1 Internal 0 10
TableEntry Create 1 13 0 1 1 Internal 0 10
TableEntry Create 1 14 * 1 1 Internal 0 10
/ Route Description
/ ----- -----------
DestinationRoute Create 1 Infostrada
DestinationRoute Create 2 Carrier Principale
DestinationRoute Create 3 Voice Application
DestinationRoute Create 4 Attendant
DestinationRoute Create 5 VTL_Roma
DestinationRoute Create 6 Linea Cellulari
DestinationRoute Create 7 Trasformnum1
DestinationRoute Create 10 Hotline
/ Route Entry DestinationExtension
/ ----- ----- --------------------
DestinationRouteEntry Create 1 1 *0002
DestinationRouteEntry Create 2 1 *0002
DestinationRouteEntry Create 3 1 *0003
DestinationRouteEntry Create 4 1 *0004
DestinationRouteEntry Create 5 1 *0006
DestinationRouteEntry Create 6 1 *0001
DestinationRouteEntry Create 6 2 *0002
DestinationRouteEntry Create 7 1 *0002
DestinationRouteEntry Create 10 1 450 (huntgroup=