SI2493-C-FS Silicon Laboratories Inc, SI2493-C-FS Datasheet - Page 46

• 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
46
%V2
Automatic Line Status Detection - Adaptive Method.
Description: Before going off-hook with the ATD, ATO, or ATA commands, the Si2493/57/34/15/04
compares the line voltage (via LVCS) to the NLIU (U85) register:
Loop Voltage
0 ≤ LVCS ≤ (0.0625 x NLIU)
(0.0625 x NLIU) < LVCS ≤ (0.85 x NLIU)
(0.85 x NLIU) < LCVS
The NLIU register is updated every 1 ms with the minimum non-zero value of LVCS in the last
30 ms. This allows the Si2493/57/34/15/04 to eliminate errors due to 50/60 Hz interference and also
adapt to relatively slow changes in the on-hook dc reference value on the telephone line. This algo-
rithm does not allow any non-zero values for NLIU below 0x0007. The host may also initialize NLIU
prior to issuing the %V2 command. Once the call has begun, the off-hook intrusion algorithm
(described in "3.5.9. Intrusion Detection—Off-Hook Condition" on page 124) operates normally. In
addition, the Si2493/57/34/15/04 reports “NO LINE” if the telephone line is completely disconnected.
If the HOI (U77, bit 11) bit is set, “LINE IN USE” is reported upon intrusion.
Table 20. Extended AT% Command Set (Continued)
Rev. 0.9
Action
Report “NO LINE” and remain on-hook.
Report “LINE IN USE” and remain on-hook.
Go off-hook and establish a modem connection.