INTRODUCTION
The CH2056, CH1799 and CH1794 (HS Modem Family) are industrial grade high-speed modem modules. Each HS Modem product supports a range of modem standards and speeds from 300bps to 14,400bps, 28,800bps, 33,600bps or 57,600bps. By using built in compression algorithms the operation speed can be expanded to the maximum DTE rate of 57.6kbps for the CH1794, 115.2kbps for the CH1799 and 230.4kbps for the CH2056. A choice of error correcting schemes is available including MNP 10 for cellular telephone applications. The HS Modem family supports Send and Receive FAX. The CH1799LL operates exclusively on non-voltage bearing leased line.
The HS Modem family is pin compatible with Cermetek’s low cost CH1786 V.22bis, 2400bps modem family. Each module in the HS Modem family is a self-contained modem and is FCC Part 68 approved and Canadian DOT approvable. Additionally, the CH1799TBR/ETBR and the CH2056TBR/ETBR products meet the European TBR21 requirements.
These ultra small modules are designed for PCB through-hole mounting and are 1.35” x 1.38” x 0.61” (nominal, 0.55” upon request) in size. The HS Modem family requires only two external interfaces: a CCITT V.24 serial interface for direct access to a UART, and a Tip and Ring RJ-11C Jack for the PSTN line connection. The HS Modem can be controlled with industry standard AT commands and is compatible with available industry communication software.

FEATURES
• Supports V.90, V.34bis, V.34, V.32bis, V.32, V.22bis, V.22A/B, V.23, V.21, Bell 212A and 103.
• CH2056 supports V.80 Synchronous operation.
• Error correcting: V.42 LAMP, MNP 2-4 and MNP10.
• Data Compression: V.42bis and MNP 5
• MNP10 Data through put enhancement for cellular operation.
• DTE serial interface with speeds up to 230.4kbps (CH2056), 115.2 (CH1799) or 57.6kbps (CH1794).
• Automatic baud rate adaptability utilizing speed sensing, flow control and data buffers.
• Send & Receive FAX class 1, Group 3 supported.
• Serial V.24, 5 volt interface.
• NVRAM directory and stored profiles.
• AT Command structure, with extensions.
• Built-in DAA with 1500 VAC RMS isolation 2122V peak surge protection.
• UL 1950 and CSA C22.2 950 Recognized (E104957).
• Leased Line version available CH1799LL
• FCC part 68 Approved/DOT CSA CS-03 Part I Approvable.
• +5 Volt operation with zero power option
• Small size: 1.35” x 1.38” x 0.61” (nominal, 0.55” upon request).
• Pin compatible with low speed/low cost CH1786
• TBR21 compliant versions available: CH1799TBR/ETBR and CH2056TBR/ETBR.