SI2493-C-GT Silicon Laboratories Inc, SI2493-C-GT Datasheet - Page 93

• Manufacturer Part Number: SI2493-C-GT
• Description: IC ISOMODEM SYSTEM-SIDE 24TSSOP
• Manufacturer: Silicon Laboratories Inc

Specifications of SI2493-C-GT

• Mfg Application Notes: SI2493/57/34/15/04, Appl Note AN93
• Data Format: V.21, V.22, V.23, V.29, V.32, V.34, V.90, V.92, Bell 103, Bell 212A
• Baud Rates: 56k
• Interface: Parallel
• Voltage - Supply: 3 V ~ 3.6 V
• Mounting Type: Surface Mount
• Package / Case: 24-TSSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

is adjustable in 3 mA units. The default value is 2
(6 mA).
Bits 4:0 (ACL): ACL provides a means of detecting a
parallel phone intrusion during the time between the
modem going off-hook and the U77[15:12] (IST) time
value. If ACL = 0, the ISOmodem has no reference and
must use the loop current sample from the first off-hook
event as a reference for parallel phone intrusion
detection.
approximate value and FACL = 0 before the first off-
hook event after powerup or reset. This allows the
updated ACL value to be used for subsequent calls and
3.3.41. U77 (GEN2)
U77 is a bit-mapped register that controls parameters
relating to intrusion detection and overcurrent detection.
U77 resets to 0x401E with a power-on or manual reset
(see Table 62).
Bits 15:12 (IST) set the delay between the time the
modem goes off-hook and the intrusion detection
algorithm begins. This register has 250 ms increments,
and the default value is 4 (1 sec).
Bit 11 (HOI) determines whether the host or modem
responds to an intrusion. HOI = 0
modem from hanging-up in response to an intrusion
without host intervention. In this case, the host monitors
U70[2] (PPD) and takes the appropriate action when
PPD is asserted indicating an intrusion. If HOI = 1
modem hangs up immediately and will not go off-hook
and dial when an intrusion is detected without host
intervention. If %V
causes the “LINE IN USE” result code upon PPD
interrupt.
15:9
7:5
4:0
Bit
8
OHSR
Name
FACL
DCL
ACL
Typically,
N
Function
Off-Hook Sample Rate for Intrusion Detection (40 ms units).
(1 second default)
Force ACL.
0 = While off-hook, ACL is automatically updated with LVCS value.
1 = While off-hook, ACL saves previously written value.
Differential Current Level (3 mA units). (6 mA default)
Absolute Current Level (3 mA units). (0 default)
commands are set, HOI also
the host
b
(default) prevents the
sets ACL
Table 61. U76 Bit Map
to
b
, the
Rev. 0.9
an
eliminates a potential detection problem if an intrusion
occurs simultaneously when the modem goes off-hook
for the first time after a powerup or reset. If ACL = 0
is ignored by the off-hook intrusion algorithm. A PPD
interrupt is generated if U79[4:0] (LVCS) is DCL less
than ACL for two consecutive samples. The ISOmodem
writes ACL with the contents of LVCS after an intrusion
with the last LVCS value before the intrusion. The
default value for ACL is 0
U76 resets to 0x3240 with a power-on or manual reset.
(See Table 61.)
Bit 9 (AOC) = 0
enabled and an overcurrent condition is detected, the
dc termination switches to 800 Ω, thus, reducing the
current. If AOC = 0, the overcurrent condition is only
reported by U70[3] (OCD).
Bits 8:0 (OHT) set the delay between the time the
modem goes off-hook and LVCS is read for an
overcurrent condition. The default value for this register
is 30 ms (see Table 62).
3.3.42. U78 (GEN3)
U78 is a bit-mapped register that controls intrusion
detection blocking and intrusion suspend. U78 resets to
0x0000 with a power-on or manual reset (see Table 63).
Bits 15:14 (IB) controls intrusion blocking after dialing
has begun. Table 63 defines the bit values and intrusion
blocking.
Bits 7:0 (IS) set the delay between the start of dialing
and the start of the intrusion algorithm when IB = 10
(see Table 63).
b
(default) disables AutoOvercurrent. If
b
.
AN93
b
, it
93
b