Upon reset, the ISOmodem is in command mode and
參數(shù)資料
型號: SI2493-D-GT
廠商: Silicon Laboratories Inc
文件頁數(shù): 11/60頁
文件大?。?/td> 0K
描述: IC ISOMODEN GLOBAL DAA 24TSSOP
標準包裝: 62
系列: *
Si2493
Rev. 1.3
19
4.2. Command Mode
Upon reset, the ISOmodem is in command mode and
accepts “AT” commands. An outgoing modem call can
be made using the “ATDT#” (tone dial) or “ATDP#”
(pulse dial) command after the device is configured. If
the handshake is successful, the modem responds with
the response codes detailed in Table 12 on page 40 and
enters data mode.
4.3. Data Mode
The Si2493 ISOmodem is in data mode while it has a
telephone line connection to another modem or is in the
process of establishing a connection.
Data protocols are available to provide error correction
to improve reliability (V.42 and MNP2-4) and data
compression to increase throughput (V.44, V.42bis and
MNP5).
Each connection between two modems in data mode
begins with a handshaking sequence. During this
sequence, the modems determine the line speed, data
protocol, and related parameters for the data link.
Configuration through AT commands determines the
range of choices available to the modem during the
negotiation process.
4.4. Fast Connect
The Si2493 supports a fast connect mode of operation
to reduce the time of a connect sequence in originate
mode. The Fast Connect modes can be enabled for
V.21, V.22, Bell103, and V.29 modulations. See AN93
for details.
4.5. V.80 Synchronous Access Mode
The Si2493 supports a V.80 synchronous access mode
of operation, which operates with an asynchronous DTE
and a synchronous DCE. See “AN93: ISOmodem
Chipset Family Designer's Guide”.
4.6. Clocking
The Si2493 contains an on-chip phase-locked loop
(PLL) and clock generator to derive all necessary
internal system clocks from a single clock input. A
32.768 kHz or 4.9152 MHz crystal can be used across
XTALI and XTALO pins to form the master clock
(±100 ppm max, ±25 ppm recommended) for the
ISOmodem. The 32.768 kHz option can provide lower
BOM costs and smaller footprint. Alternatively, a clock
input of 27 MHz, 4.9152 MHz, or 32.768 kHz can be
provided to XTALI if that clock source is available in the
system. A 4.9152 MHz clock input is the default clock
option.
Other clock options are selected at power-up
through reset strapping. Refer to AN93 for details.
4.7. Low-Power Modes
The Si2493 provides multiple low power modes. Using
the
S24
S-register,
the
Si2493
can
be
set
to
automatically enter sleep mode after a pre-programmed
time of inactivity with either the DTE or the remote
modem. The sleep mode is entered after (S24) seconds
have passed since the last DTE activity, after the
transmit FIFO is empty, and after the last data are
received from the remote modem.
Additionally, the Si2493 can be placed in wake-on-ring-
mode using the command, AT&Z. In either mode, the
ISOmodem remains in the sleep state until one of the
following occurs:
A 1-to-0 transition on TXD (UART mode).
A 1-to-0 transition on SS (SPI mode).
A 1-to-0 transition on CS (parallel mode).
An incoming ring is detected.
A parallel telephone is picked up.
Line polarity reversal
The Si2493 may also be placed in a complete
powerdown mode. Once the Si2493 completely powers
down, it can only be powered back on via the RESET
pin.
4.8. Data Compression
The modem can achieve DTE (host-to-ISOmodem)
speeds greater than the maximum DCE (modem-to-
modem) speed through the use of a data compression
protocol. The compression protocols available are the
ITU-T V.44, V.42bis, and MNP5 protocols. Data
compression
attempts
to
increase
throughput
by
compressing the data before actually sending it. Thus,
the modem is able to transmit more data in a given
period of time.
4.9. Error Correction
The Si2493 ISOmodem can employ error correction
(reliable) protocols to ensure error-free delivery of
asynchronous data sent between the host and the
remote end. The Si2493 supports V.42 and MNP2-4
error
correction
protocols.
V.42
(LAPM)
is
most
commonly used and is enabled by default.
4.10. Wire Mode
Wire mode is used to communicate with standard non-
error correcting modems. When optioned with \N3, the
Si2493 falls back to wire mode if it fails in an attempt to
negotiate a V.42 link with the remote modem. Error
correction and data compression are not active in wire
mode.
相關PDF資料
PDF描述
SI2494-A-GM IC ISOMODEM 56KBPS 38-QFN
SI3000-C-GS IC VOICE CODEC 3.3V/5V 16SOIC
SI3011-F-FS IC VOICE DAA GCI/PCM/SPI 16SOIC
SI3012-KS IC LINE-SIDE DAA 16SOIC
SI3019-F-FS IC LINE-SIDE DAA 16SOIC
相關代理商/技術參數(shù)
參數(shù)描述
SI2493-D-GTR 制造商:Silicon Laboratories Inc 功能描述:56 KBPS, V.92 ISOMODEM SYSTEM-SIDE - LEAD-FREE - Tape and Reel 制造商:Silicon Laboratories Inc 功能描述:IC ISOMODEN GLOBAL DAA 24TSSOP 制造商:Silicon Laboratories Inc 功能描述:56 kbps V92 ISOmodem System-Side PBF
Si2493-E-FT 制造商:SILABS 制造商全稱:SILABS 功能描述:Evaluation Board Rev 5.0 for the Si2493/57/34/15/04
Si2493FS08-EVB 功能描述:網(wǎng)絡開發(fā)工具 16-pin Si2493+Si3008 ISOmodem Eval Board RoHS:否 制造商:Rabbit Semiconductor 產(chǎn)品:Development Kits 類型:Ethernet to Wi-Fi Bridges 工具用于評估:RCM6600W 數(shù)據(jù)速率:20 Mbps, 40 Mbps 接口類型:802.11 b/g, Ethernet 工作電源電壓:3.3 V
Si2493FS18-EVB 功能描述:網(wǎng)絡開發(fā)工具 16-pin Si2493+Si3018 ISOmodem Eval Board RoHS:否 制造商:Rabbit Semiconductor 產(chǎn)品:Development Kits 類型:Ethernet to Wi-Fi Bridges 工具用于評估:RCM6600W 數(shù)據(jù)速率:20 Mbps, 40 Mbps 接口類型:802.11 b/g, Ethernet 工作電源電壓:3.3 V
SI2493-FT 功能描述:電信線路管理 IC CONTACT SILICON LABS FOR AVAILABILITY RoHS:否 制造商:STMicroelectronics 產(chǎn)品:PHY 接口類型:UART 電源電壓-最大:18 V 電源電壓-最小:8 V 電源電流:30 mA 最大工作溫度:+ 85 C 最小工作溫度:- 40 C 安裝風格:SMD/SMT 封裝 / 箱體:VFQFPN-48 封裝:Tray