si2401 Silicon Laboratories, si2401 Datasheet - Page 28

• Manufacturer Part Number: si2401
• Description: V.22bis Isomodem With Integrated Global Daa
• Manufacturer: Silicon Laboratories

Si2401
send the first SIA block after the “c” is received. Once
the block is transmitted, the modem can monitor for the
acknowledge
sequence:
1. Place the Si2401 in command mode by pulsing the
2. Issue the “ATX1” command to turn the modem
3. Monitor for a positive (negative) acknowledgment “P”
4. The modem, still in command mode, can be placed
This sequence can be repeated for long messages.
5.5. Modem Result Codes and Call
Table 14 shows the modem result codes that can be
used in call progress monitoring. All result codes are a
single character to speed up communication and ease
host processing.
28
ESCAPE pin (Si2401 pin 14). The “+++” and “ninth-
bit” escape modes operate in the “!2” mode but are
not recommended because they can send unwanted
characters to the remote modem.
transmitter off and begin monitoring for the
acknowledgment tones.
(“N”) after the tone has been detected for at least
400 ms.
online as a transmitter by issuing the “ATX2”
command or a receiver by issuing the “ATX3”
command. If tonal acknowledgement is not used, the
host can toggle the ESCAPE pin to place the Si2401
in the command mode and issue an “ATX2” or an
“ATX3” command to reverse data direction.
Progress
tone
by
completing
the
following
Rev. 1.0
Command
m
O
H
K
N
R
a
b
c
d
k
L
n
v
x
^
f
I
r
t
,
i
l
Table 14. Modem Result Codes
No Phone Line Detected
No Carrier Detected
No Dial tone (time-out set by CW
Incoming Ring Signal Detected
Function
British Telecom Caller ID Idle Tone
Alert Detected
Busy Tone Detected
Connect
Connect 1200 bps (when pro-
grammed as V.22bis modem)
Hookswitch Flash or Battery Reversal
Detected
Modem Automatically Hanging Up in
!2, !1
Intrusion Completed (parallel phone
back on-hook)
Intrusion Detected (parallel phone off-
hook on the line)
Kissoff Tone Detected
Contact ID Kissoff Tone too long (!1)
Phone Line Detected
Caller ID Mark Signal Detected
[S02])
Modem OK Response
Ringback Tone Detected
Dial Tone
Connect 75 bps TX (V.23 originate
only)
Overcurrent State Detected After an
Off-Hook Event
Kissoff tone detection required
Dialing Complete