SI2457-D-FT Silicon Laboratories Inc, SI2457-D-FT Datasheet - Page 119

• Manufacturer Part Number: SI2457-D-FT
• Description: IC ISOMODEM SYSTEM-SIDE 24TSSOP
• Manufacturer: Silicon Laboratories Inc

Specifications of SI2457-D-FT

• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

5.7.20. U80 (Transmit Delay for V.22 Fast Connect)
U80 controls delay parameters when the modem is in V.22 Fast Connect mode (+MS=V22, AT:U7A,3) and the
server does not respond with a short answer tone prior to scrambled data or HDLC flags. U80 configures the
modem to operate without these tones. Bit 15 turns this function on. After the end of dialing, the modem waits for a
time set by U80 [14:0], then begins transmitting scrambled data (or HDLC Flags). The delay units are 1/600 s. For
example, to command the modem to begin transmitting three seconds after the end of dialing:
3 x 600 = 1800 = 0x0708. Issue command AT:U80,8708.
This register is only used when U7A[4] = 0.
U80 XMITDEL Transmit Delay for V.22 Fast Connect
10:2
Bit
15
14
13
12
11
0
1
14:0
Bit
15
Reserved Read returns zero.
Reserved Read returns zero.
Reserved Read returns zero.
Name
CALD
TCAL
ATZD
NLM
FDP
V22FCDEL When V22FCDF = 1, V22FCDEL is the delay between end of dialing and sending
V22FCDF 0 = Normal operation (default)
Name
Host software recommended to always set this to bit.
0 = Enables “No Loop Current” Detect.
1 = Disables “No Loop Current” Detect.
0 = Timed calibration disabled.
1 = Timed calibration. The time between off-hook and calibration is set in U54 (OHCT).
0 = No calibration during dial.
1 = Calibrate during dial. It is recommended that the dial string start with “,” to prevent first
digit loss.
0 = ATZ enabled.
1 = ATZ disabled.
0 = FSK data processing stops when carrier is lost.
1 = FSK data processing continues for two bytes after carrier is lost.
1 = Transmit scrambled data (or HDLC flags) after delay set in bits 14 - 0
scrambled data (or HDLC flags) in 1/600 s units. Default is 0x0168 (600 ms).
When V22FCDEL = 0, V22FCDEL is the delay between ANS tone detected to start of
training.
Table 81. U7D Bit Map
Rev. 1.3
Function
Function
AN93
119