Paradyne 3800 - Manual (Page 102)

D. CCITT V.25 bis Dialing Commands and Response
D-7 3830-A2-GB91-20 November 1996
Command Response
A Command Response indicates that the command entered was a valid
or invalid entry. Command Response includes Valid (VAL) and Invalid
(INV).
Valid (VAL)
The VAL response indicates that the modem has accepted the V.25 bis
command issued by the DTE. VAL is similar to the AT result code OK.
Invalid (INV)
The INV response indicates that the modem has received an incorrect
V.25 bis command from the DTE. INV is similar to the AT result code
ERROR.
The INV response format is:
INVxx
Where: xx is
CU command unknown
MS message syntax error
PS
parameter syntax error
PV parameter value error
Table D-1 lists V.25 bis commands supported by the Model 3830
modem.