73K224BL
V.22bis, V.22, V.21, Bell 212A, 103
Single-Chip Modem w/ Integrated Hybrid
DATA SHEET
DETECT REGISTER (continued)
DR
D7
D6
D5
D4
D3
D2
D1
D0
ADDR
010
RECEIVE
LEVEL
INDICATOR
S1
PATTERN
DETECT
RECEIVE
DATA
UNSCR.
MARK
DETECT
CARR.
DETECT
ANSWER
TONES
DETECT
CALL
PROG.
DETECT
SIGNAL
QUALITY
INDICATOR
BIT
NAME
CONDITION
DESCRIPTION
No answer tone detected.
D2
Answer Tone
Received
0
1
In call init mode, indicates detection of 2225 Hz answer
tone in Bell mode (TR bit D0 = 0) or 2100 Hz if in CCITT
mode (TR bit D0 = 1). The device must be in originate
mode for detection of answer tone. Both answer tones are
detected in demodulation mode.
D3
D4
Carrier Detect
0
1
No carrier detected in the receive channel.
Indicated carrier has been detected in the received
channel.
Unscrambled
Mark Detect
0
1
No unscrambled mark.
Indicates detection of unscrambled marks in the received
data. Should be time qualified by software.
D5
D6
Receive Data
Continuously outputs the received data stream. This data is
the same as that output on the RXD pin, but it is not
disabled when RXD is tri-stated.
S1 Pattern
Detect
0
1
No S1 pattern being received.
S1 pattern detected. Should be time qualified by software.
S1 pattern is defined as a double di-bit (001100..)
unscrambled 1200 bit/s DPSK signal. Pattern must be
aligned with baud clock to be detected.
D7
Receive Level
Indicator
0
1
Received signal level below threshold, (typical ≈ -25 dBm0);
can use receive gain boost (+18 dB).
Received signal above threshold.
Page: 13 of 33
© 2005, 2008 TERIDIAN Semiconductor Corporation
Rev 7.1
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