SI2493-C-FS Silicon Laboratories Inc, SI2493-C-FS Datasheet - Page 94

• Manufacturer Part Number: SI2493-C-FS
• Description: IC ISOMODEM SYSTEM-SIDE 16SOIC
• Manufacturer: Silicon Laboratories Inc

Specifications of SI2493-C-FS

• 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: UART
• Voltage - Supply: 3 V ~ 3.6 V
• Mounting Type: Surface Mount
• Package / Case: 16-SOIC (3.9mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AN93
3.3.43. U79 (GEN4)
U79 is a bit-mapped register. Bits 15:6 are reserved.
Bits 5:0 represent the line voltage, loop current, or on-
hook line monitor (see Table 64). While the modem is
on-hook, the value in the LVCS register measures loop
voltage (see Table 65). This value can be used to
determine if a line is connected or if a parallel phone or
other device goes off-hook or on-hook. The accuracy of
the LVCS bits is ±20%. When the modem goes off-hook,
the value in the LVCS register measures loop current.
LVCS can indicate when a parallel phone or other
device goes on-hook or off-hook and detect whether
enough loop current is available for the modem to
operate or if an overload condition exists.
94
00000 = No line connected.
00001 = Minimum line voltage (VMIN = 2.5 V ±0.5 V).
11111 = Maximum line voltage (87 V ±20%)
15:12
15:14
13:8
8:0
7:0
Bit
Bit
11
10
9
Reserved Read returns zero.
Reserved Read returns zero.
OHT[8:0]
Name
Name
AOC
On-Hook Voltage Monitor Mode
HOI
IST
IB
IS
Function
Intrusion Settling Time (250 ms units) 1 second default.
Hang-Up On Intrusion.
0 = ISOmodem does not automatically hang up after an off-hook PPD interrupt.
1 = ISOmodem automatically hangs up after an off-hook PPD interrupt.
AutoOvercurrent.
0 = Disable.
1 = Enable.
Off-Hook Time (1 ms units) 30 ms default.
Function
Intrusion Blocking.
00 = No intrusion blocking.
01 = Intrusion disabled from start of dial to end of dial.
10 = Intrusion disabled from start of dial to IS register time-out.
11 = Intrusion disabled from start of dial to “CONNECT XXX”, “NO DIALTONE”, or “NO CAR-
RIER”.
Intrusion Suspend (500 ms units) default = 0 ms.
Table 64. Monitor Mode Values
Table 62. U77 Bit Map
Table 63. U78 Bit Map
Rev. 0.9
00000 = No loop current.
00001 = Minimum loop current.
11110 = Maximum loop current.
11111 = Loop current is excessive (overload). Overload
> 155 mA (60 mA in CTR21 mode).
The line voltage monitor full scale may be modified by
changing R5 as follows:
V
See Table 65. LVCS is backward-compatible with older
ISOmodem
not reflect loop polarity. See U6C (LVS) [15:8] for 1 V/bit
resolution and signed 2s complement format and
U63(LCS)
measurement. The values for loop voltage and loop
current in U79 are calculated by the modem from the
values in U6C and U63 respectively.
MAX
= V
MIN
Off-Hook Current Monitor Mode
®
[15:8]
+ 4.2 (10M + R5 + 1.78k)/(R5 +1.78k)/5
revisions. The value is absolute and does
for
1.1 mA/bit
loop
current