AT Commands
F-14 AT Commands
NOTES
•
Hardware flow control overrides &C and \D settings for CTS. (See \Q.)
•
The modem ignores &C and \D settings while connected in V.23 half-duplex
direct mode (%F3) or ITU-T V.13 (&R2).
•
When \D4 is set, &D should be set to a value greater than 0.
•
ITU-T recommends that DSR comes On when establishing a connection and
drops when the connection ends.
•
ITU-T recommends that CTS follows DTR while in command state; drop either
when answer tone is detected when originating, when going off hook when
answering, or when connection ends; and follows connection status during
connection.
Use the following table when your computer requires DSR and CTS to be Off. It shows
&C and \D settings and the result of combining the two commands.
&C
\D
Result
0
0
DCD On, DSR On, CTS On
0
1
DCD On, DSR On, CTS On
0
2
DCD On, DSR On, CTS On
0
3
DCD On, DSR complies with the ITU-T
recommendations, CTS On
0
4
DCD On, CTS/DSR comply with the ITU-T
recommendations
1
0
DCD follows modem carrier, DSR On, CTS On
1
1
DCD follows modem carrier, DSR follows off hook,
CTS follows DCD
1
2
DCD follows modem carrier, DSR and CTS both
follow DCD setting
1
3
DCD follows modem carrier, DSR complies with the
ITU-T recommendations, CTS On
1
4
DCD follows modem carrier, CTS/DSR comply with
the ITU-T recommendations
