3com MSR 20-20 참조 매뉴얼

You may use this command to adapt values of bits C and D to different line 
signaling coding schemes. The settings of bits A and B in this command however 
are not necessarily the real ones during transmission.

cas and reverse.

# Set bits C and D of R2 line signaling to 11.

<Sysname> system-view

[Sysname] controller e1 1/0

[Sysname-e1 1/0] timeslot-set 0 timeslot-list 1-31 signal r2

[Sysname-e1 1/0] cas 0

[Sysname-cas1/0:0] renew 0011 

reverse ABCD

R2 CAS view

ABCD: Indicates whether corresponding ABCD bits in R2 signaling need inversion. 
Each argument in this command takes either of the two values: 0 for normal or 1 
for inversion. The default is 0000, that is, inversion disabled.

Use the reverse command to configure line signal inversion mode.

Use the undo reverse command to invert ABCD bits of the current line signaling 
whose values are “1” after the reverse command is executed.

This command applies to R2 signaling only.

You may configure an interface to invert the values of any ABCD bits before 
sending or after receiving a line signal by replacing 0 with 1 or vice versa.

cas and renew.

# Invert the values of bits B and D in R2 line signaling.

<Sysname> system-view

[Sysname] controller e1 1/0

[Sysname-e1 1/0] timeslot-set 0 timeslot-list 1-31 signal r2

[Sysname-e1 1/0] cas 0

[Sysname-cas1/0:0] reverse 0101