Control Data Cyber 170 State Hardware Reference Manual page 171

Function
76d
Function A on chamel d
FAN d
This instruction sends the external function code in the lower 12 bits of the A
register on channel d.
NOTE
If this instruction executes with bit 5 of d
clear and the channel active,
PP
execution
stops until a deadstart or another PP causes
the channel to become inactive. If bit 5 of d
is set and the channel is active, the program
continues at P plus 1 . Neither the function
signal nor the function word transmits. The
channel remains active, and execution continues.
Function m on channel d FNC m,d
This instruction sends the external function code specified by m on channel d.
NOTE
If
this instruction executes with bit 5 of d
clear and the channel active,
PP
execution
stops until a deadstart or another
PP
causes
the channel to become inactive.
If bit 5 of d
is set and the channel is active, the program
continues at
P plus 2 . Neither the function
signal nor the function word transmits. The
channel remains active, and execution continues.