PRELIMINARY
CH224ATF
CH224ATF
Complete 2400 bps Modem Module
INTRODUCTION
The CH224ATF is a complete FCC Part 68 pre-
approved, 2400 bps full function modem solu-
tion; incorporating an on-board Data Access
Arrangement (DAA) in a small footprint,
socket-able packaging format (2.5” L x 1.0 W x
0.45” H).
This product is specifically designed for use as
direct re-placement 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 a 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.
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
Serial TTL:
Operating
155mW
Sleep
35mW
• Single +5VDC power supply
©1999 Cermetek Microelectronics, Inc.
1
Document No. 607-0005 Rev.A (11/99)