5.0 S Registers
RC224ATL/224ATLV
EmbeddedModem Family
Table 5-2. S Register Description (4 of 8)
Register
Default
Range
Units
Description
—
S21
00
Bit Mapped
Bit Mapped Options. S21 is the modem register with the following
bit functions:
Bit 0
Telco Jack (See &J Command)
0
1
&J0—11/RJ-45S (factory default)
&J1—RJ-12/RJ-13
Bit 1
Bit 2
Reserved
Ready to Send (RTS)/Clear to Send (CTS). (See &R
Command)
0
1
&R0—CTS tracks RTS (not supported)
&R1—RTS is ignored (factory default)
Bit 3, 4 Data Terminal Ready (DTR) (See &D Command)
4 3
0 0
0 1
&D0—Modem ignores DTR (factory default)
&D1—Modem goes to command state if
ON-to-OFF transition on DTR
1 0
1 1
&D2–Modem “hangs up” if ON-to-OFF
transition on DTR
&D3—Modem goes to initialization state if
ON-to-OFF transition on DTR
Bit 5
Bit 6
Bit 7
Data Carrier Detect (DCD) (See &C Command)
0
1
&C0—DCD is always on (factory default)
&C1—An ON condition on DCD indicates the
presence of a valid data carrier
Data Set Ready (DSR) (See &S Command)
0
1
&S0—DSR is always on
&S1—DSR is turned on at the start of
handshaking
Long Space Disconnect (See Y Command)
0
1
&Y0—Disabled (factory default)
&Y1—Enabled
5-6
Conexant
D224ATLVDSC
CONEXANT [ CONEXANT SYSTEMS, INC ]
