CRMET CH224ATF Datasheet

CH224ATF
Complete 2400 bps Modem Module
INTRODUCTION
The CH224ATF is a complete FCC Part 68 pre­approved, 2400 bps full function modem solution; incorporating an on-board Data Access Arrangement (DAA) in a small footprint, socket­able packaging format (2.5” L x 1.0 W x 0.45” H).
This product is specifically designed for use as a direct replacement for Conexant/Rockwell’s SocketModem (serial TTL I/O option, Part No. SF224ATF-H1-D5-A0-P1
).
This modem provides a fast and convenient way to integrate PSTN connectivity into any OEM product while utilizing a small portion of PCB area. The CH224ATF requires two external interfaces: a CCITT V.24 serial interface that is routed directly from the UART or UART interface, and a TIP and RING interface, which is connected directly to a conventional RJ-11 jack for the PSTN line connection. The CH224ATF also has various indicator and status lines to monitor operations or to establish triggers. The CH224ATF modem is controlled by industry standard “AT” commands and is compatible with available industry communication software.
The device supports asynchronous operation at 2400 bps, 1200 bps, and 300 bps to both Bell and CCIT standards. The resident PSTN line interface is FCC Part 68 approved, and is also Canadian DOC approveable, and can be approved in other countries that require 1500VAC RMS isolation.
Figure 1. Functional Block Diagram of CH224ATF
FEATURES
FCC Part 68 pre-approved
UL1950, 3rd edition listed
1500 Vrms isolation
Complete solution: on-board DAA
Data modes
- CCITT v.22 bis (2400 bps), V.22 (1200 bps)
- Bell 212A (1200 bps) and 103 (300 bps)
- Enhanced AT commands
Group 3 fax modes
- V.29 (6900/7200 bps) transmit
- V.27 ter (4800/2400 bps) transmit and receive
- V.21 Channel 2 (300 bps) transmit and receive
EIA-578 Service Class 1 commands
V.42/MNP2-4 and V.42 bis/MNP5 support
without additional hardware
Data/fax discriminator and auto answering
Communications software compatible
Serial asynchronous DTE interface
NVRAM interface allows storage of two
user configurations and four 36-digit dial strings
Automatic adaptive/fixed compromise equalization
Programmable sleep mode
Full-duplex data mode test capabilities:
Analog loop, local digital loop, and remote digital loop
Half-duplex fax mode test capabilities
Automatic format/speed sensing
Low power consumption (typical):
Interface Operating Sleep
Serial TTL: 155mW 35mW
Single +5VDC power supply
TECHNICAL SPECIFICATIONS
General
The CH224ATF modem is a full-featured, self­contained data/fax solution. External micro­controller for data or fax control functions are fully supported and controlled through the AT command set.
2001 Cermetek Microelectronics, Inc. Page 1 Document No. 607-0005 Revision B1 (05/02)
Cermetek Microelectronics, Inc. CH224ATF Complete 2400 bps Modem Module
Data modes perform complete handshake and data rate negotiations. All tone and pattern detection required by the applicable CCITT or Bell standard are supported.
Fax modes support Group 3 fax requirements. Fax data and fax control (V.21 300 bps) performed by the modem is controlled and monitored through the fax EIA-578 Class 1 insertion/deletion, and CRC generation/checking is provided.
Both transmit and receive fax data is buffered within the modem. Data transfer to and from the DTE is flow controlled by XON/XOFF.
Configurations and Rates
The supported modem configurations and signaling rates are listed in Table 1. In data modes with serial interface selected, DTE rate offsets of +1%, -2.5% are accommodated by adding/deleting stop bits are required. In fax modes, the DTE rate is 19200 bps.
Operation
Modem operation is controlled by AT commands (Table 2), fax service class 1 commands (Table 3), and supporting S registers (Table 4). Result codes and messages are listed in Table 5.
Data Modes: Data rate selection is determined by the speed of the originating and answering modems:
Originate Modem Connect Speed Based on Answer Rate Modem Rate (bps) (bps) 300 1200 2400
300 300 300 300
1200 1200 1200 1200
2400 1200 1200 2400
Fax Modes: Fax modes are negotiated as
defined in T.30 and are implemented by AT+F commands. The AT+FCLASS=1 command causes entry into the fax mode from the data mode. Most other fax class 1 commands, which start with the AT+F prefix, are valid only in the fax mode.All data commands are valid in the fax mode except A/, On & Tn, and the escape sequence (+++). The AT+FCLASS=0 command terminates the fax mode and causes entry into the data mode.
AT Command Format
Each command line must start with the AT prefix and be terminated with a carriage return (CR). Several commands may be included on one command line. A command line may contain up to 40 characters excluding the AT prefix and the terminating CR. A separator is not required between data commands. A semicolon (;) separator is required between fax commands.
AT commands are composed of 10-bit ASCII encoded asynchronous characters. The character format in data mode is 8 data bits with no parity, or 7 data bits with even, odd, or no (two stop bits) parity, at a data rate of 19200, 2400, 1200, or 300 bps. The character format in fax mode is 8 data bits with no parity at 19200 bps.
Data Modulation
The data modulation conforms to V.29, V.27 ter, V.22 bis, V.22, V.21, Bell212A, or Bell 103, depending on the selected configuration. Transmitter and receiver spectrum shaping is provided in accordance with the applicable standard.
Equalization
Automatic adaptive qualization as well as fixed compromised equalization is provided to compensate for line distortions and to minimize the effects of the intersymbol interference.
Scrambler/Descrambler
The modem incorporates a self-synchronizing scrambler/descrambler satisfying the applicable CCITT or Bell requirements.
2001 Cermetek Microelectronics, Inc. Page 2 Document No. 607-0005 Revision B1 (05/02)
Cermetek Microelectronics, Inc. CH224ATF Complete 2400 bps Modem Module
Table 1. Configurations and Rates
Configurati
on
Modulation Transmitter Carrier
Frequency (Hz) +
0.01%
Data Rate
(bps)
Baud
(Symbols/
Sec.)
Bits Per
Symbol
Constellation
Points
Data Mode
V.22 V.22
Bell 212A
Bell 103
QAM DPSK DPSK
FSK
Answer
2400 2400 2400 2225
2025 S
Originate
1200 1200 1200
1270 M
1070 S
2400 1200 1200
300
600 600 600 300
4 2 2 1
16
4 4 1
Fax Mode
V.29 V.22
Bell 212A
Bell 103
QAM DPSK DPSK
FSK
Receive
N/A
N/A 1800 1800
1650 M
1850 S
Transmit
1700 1700 1800 1800
1650 M
1850 S
9600 7200 4800 2400 300
2400 2400 1600 1200 300
4 3 3 2 1
16
8 8 4 1
Notes:
Legend: QAM = Quadrature Amplitude Modulation M = Mark Condition
DPSK = Differential Phase Shift Keying S = Space Condition FSK = Frequency Shift Keying N/A = Not Applicable
Table 2. “AT” Command Set Summary
Command Function Command Function
A/ Re-execute command &Jn Telephone jack control A Answer a call &L0 Dial-up line operation Bn Select CCITT or Bell Mode &M0 Asynchronous mode Cn Carrier control &Pn Pulse dial make/break ratio Dn Dial modifier &Q0 Asynchronous mode En Command echo &Sn DSR override F1 On-line character echo option &Tn Test and diagnostic Hn Disconnect (Hangup) &V Display current configurations In Identification &Wn Store current configuration Ln Speaker volume &X0 Asynchronous data transmission Mn Speaker control &Yn Select default profile On Go on-line &Zn=x Store dial string to location n P Force pulse dialing %Dn DTMF Level Attenuation Qn Quiet Result codes control %J Load Secondary Defaults Sn Select S register as default %Ln Transmit Level Attenuation Sn=v Set default S register to value Dial Modifier Function Sn? Return the value of S register P Pulse Dial T Force DTMF dialing R Originate Call in Answer Mode Vn Report codes form S=n Dial Stored Number Xn Extended result codes T Tone Dial Yn Long space disconnect W Wait for Dial Tone Zn Soft reset and restore profile ; Return to Idle State &Cn RLSD (DCD) option @ Wait for Quiet Answer Command &Dn DTR option ! Flash Hook &F Recall (restore)factory profile , Pause &Gn Select guard tone 0-9, A, B, C, D, #, * Dial Digits/ Characters
2001 Cermetek Microelectronics, Inc. Page 3 Document No. 607-0005 Revision B1 (05/02)
Cermetek Microelectronics, Inc. CH224ATF Complete 2400 bps Modem Module
Table 3. FAX Command Set Summary Table 4. Register Summary
FAX Command Function
Register Function
+FCLASS=n Service class SO* Rings to Auto –Answer +F<command>? Report Active Configuration S1 Ring Counter +F<command>=? Report Operating Capabilities S2 Escape Character +FAA=n Data/Fax Auto Answer S3 Carriage Return Character +FF Enhanced flow Control S4 Line Feed Character +FTS=n Stop Transmissions & Wait S5 Backspace Character +FRS=n Receive Silence S6 Maximum time to Wait for Dial
Tone +FTM=n Transmit Data S7 Wait for Carrier +FRM=n Receive Data S8 Pause Time for Comma +FTH=n Transmit Data with HDLC
Framing
S9 Carrier Detect Response Time
+FRT=n Receive Data with HDLC
Framing
S10 Carrier Loss Disconnect Time
+FRTn Receive Test Data S11 DTMF dialing Speed +FTTn=m Transmit Test Data S12 Escape Prompt Delay +Hn Rockwell Protocol Interface (RPI
Enable)
S14* General Bit mapped Options (&T)
S16 Fax Mode Null Byte Timer
Table 5. Results Codes & Messages
S17 Test Timer
Digit
Code
Word Code Meaning
S18* Rockwell Protocol Interface
Speed 0 OK Command line executed without
errors
S19 Fax ode Inactivity Timer
1 CONNECT Connection at 300bps S20 General bit Mapped Options 2 RING Ringing signal detected S21* General bit Mapped Options 3 NO
CARRIER
Carrier lost or never present S22* General bit Mapped Options
4 ERROR Invalid command, checksum,
error in command line, or command line exceeds 40 characters
S23* General Bit Mapped Options
5 CONNECT
1200
Connection at 1200 bps S24 Sleep Inactivity Timer
6 NO DIAL
TONE
No dialtone detected S25* Delay to DTR Off
7 BUSY Busy signal detected S26* RTS-to-CTS Delay 8 NO
ANSWER
No silence detected when dialing a system not providing a dialtone
S27* General Bit Mapped Options
10 CONNECT
2400
Connection at 2400 bps S28* General Bit-Mapped Options
+F4 +FCERROR Fax carrier error * Register value may be stored in one of two user
profiles with the AT&W command.
13 DATA Connected as data modem
during auto answer
15 FAX Connected as fax modem during
auto answer
Data/Fax Auto Answering
The modem can automatically determine if the incoming call is from a data or fax modem, make the appropriate connection, and inform the DTE of the connection type.
2001 Cermetek Microelectronics, Inc. Page 4 Document No. 607-0005 Revision B1 (05/02)
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