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Chapter 18: V.25bis Dialing Commands
18.2 Call Responses
A call response indicates if the command was accepted by the ISDN TA/V.
Call response includes call failure indication (
CFI
) and call connecting
(
CNX
).
18.2.1 C
ALL
F
AILURE
I
NDICATION
(CFI)
The
CFI
response is issued to the DTE if the ISDN TA/V fails a
CRN
or
CRS
command.
CFI
is similar to the AT result codes
BUSY
,
NO ANSWER
,
NO
CARRIER
,
NO DIALTONE
, and
ERROR
. The
CFI
response is:
CFI
xx
Where
xx
is:
ET
Engaged tone. Is similar to the result code BUSY.
NS
Number not stored. Is similar to the result code ERROR.
CB
Local DCE busy. Is similar to the result code ERROR.
RT
Timeout on ring tone. Is similar to the result code NO
CARRIER.
AB
Abort call on-timeout. Is similar to the result codes
NO DIALTONE and ERROR.
NT
Answer tone not detected. Is similar to the result code
NO ANSWER.
FC
Forbidden call. Is similar to the result code ERROR.
18.2.2 C
ALL
C
ONNECTING
R
ESPONSE
(CNX)
The CNX response informs the DTE that the ISDN TA/V has connected to
the remote ISDN TA/V. CNX is similar to the AT result code CONNECT.
The CNX response format is CNX.