Tube Serial
number
Tube
passage
marker
Meaning of tube passage “light” Meaning of tube passage “No light”
1
A Hall call communication of address
dial-up 1 normal
hall call communication of address
dial-up 1 deviant
B Outside call communication of
address dial-up 2 normal
Outside call communication of
address dial-up 2 deviant
C Outside call communication of
address dial-up 3 normal
Outside call communic
ation of
address dial-up 3 deviant
D Outside call communication of
address dial-up 4 normal
Outside call communication of
address dial-up 4 deviant
E Outside call communication of
address dial-up 5 normal
Outside call communication of
address dial-up 5 deviant
F Outside call communication of
address dial-up 6 normal
Outside call communication of
address dial-up 6 deviant
G Outside call communication of
address dial-up 7 normal
Outside call communication of
address dial-up 7 deviant
DP Outside call communication of
address dial-up 8 normal
Outside call communication of
address dial-up 8 deviant
2
A Outside call communication of
address dial-up 9 normal
Outside call communication of
address dial-up 9 deviant
B Outside call communication of
address dial-up 10 normal
Outside call communication of
address dia
l-up 10 deviant
C Outside call communication of
address dial-up 11 normal
Outside call communication of
address dial-up 11 deviant
D Outside call communication of
address dial-up 12 normal
Outside call communication of
address dial-up 12 deviant
E Outside call communication of
address dial-up 13 normal
Outside call communication of
address dial-up 13 deviant
F Outside call communication of
address dial-up 14
normal
Outside call communication of
address dial-up 14 deviant
G Outside call communication of
address dial-up 15 normal
Outside call communication of
address dial-up 15 deviant
DP Outside call communication of
address dial-up 16 normal
Outside call communication of
address dial-up 16 deviant