SI3015-F-FS View Datasheet(PDF) - Silicon Laboratories

Part Name

Description

Manufacturer

SI3015-F-FS

V.22BIS ISOMODEM® CHIPSET WITH ERROR CORRECTION

Silicon Laboratories 

Si2403

4.8. Error Correction

The ISOmodem® chipset can employ error-correction

(reliable) protocols to ensure error-free delivery of

asynchronous data sent between the host and the

remote end. The Si2403 supports V.42 and MNP2-4

error correction protocols. V.42 (LAPM) is most

commonly used and is enabled by default.

4.9. Wire Mode

Wire mode is used to communicate with standard non-

error correcting modems. When optioned with \N3, the

ISOmodem chipset falls back to wire mode if it fails in

an attempt to negotiate a V.42 or MNP link with the

remote modem. Error correction is not active in wire

mode.

4.10. Caller ID Operation

The ISOmodem chipset supports full type 1 caller ID

detection and decode for the US Bellcore, European

ETSI, UK, and Japanese caller ID protocols. Caller ID is

enabled via the +VCID and +VCDT commands.

4.11. Parallel Phone Detection

This allows the host to avoid interrupting another phone

call when the phone line is already in use and to

intelligently handle an interruption when the Si2403 is

using the phone line.

4.11.1. On-Hook Line-in-Use Detection

When the ISOmodem chipset is sharing the telephone

line with other devices, it is important that it not interrupt

a call in progress. To detect whether another device is

using the shared telephone line, the host can use the

Si2403 to monitor the TIP-RING dc voltage with the

LVCS (Line Voltage and Current Sense) register (U79,

bits 4:0). See Figure 6 on page 19. See also the %Vn

commands for automatic line-in-use detection.

4.11.2. Off-Hook Intrusion Detection

When the ISOmodem chipset is off-hook, an algorithm is

implemented in the Si2403 to automatically monitor the

TIP-RING loop current via the LVCS register. When the

Si2403 is off-hook, the LVCS register switches from

representing the TIP-RING voltage to representing the

TIP-RING current. (See Figure 7 on page 19.) Upon

detecting an intrusion, the Si2403 alerts the host to the

condition via the INT pin.

The ISOmodem chipset is able to detect when another

telephone, modem, or other device is using the phone

line.

18

Rev. 1.2

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