Cermetek Microelectronics, Inc.
High Speed Internet Modem Family
2005 Cermetek Microelectronics, Inc.
Page 5
Document No. 607-0017 Revision I1 (05/05)
Internal Modem.
The internal modem is used to
establish a data connection with the ISP. The CH2160
contains a V.90 internal modem while the CH2124
contains a V.22bis internal modem. The internal
modem can be controlled with Hayes AT commands
and is compatible with industry standard
communication software. Refer to Cermetek
publication, AT Commands and S-Registers, for a more
detailed discussion of the Hayes AT commands
supported by the iModem product family.
When operating in standard analog modem mode, the
maximum Data Terminal Equipment (DTE)/Host system
communication speed is established by the maximum
speed available from the DTE/Host and is not limited by
the iModem product.
IMPORTANT NOTICE
AS DELIVERED FROM THE FACTORY, all
@T
®
command communication between the CH2160
(CH2124) iModem and the host processor is
conducted over the serial interface at 57.6/19.2kbps
(2400bps).
CH21XX DTE Speed.
AS DELIVERED FROM THE
FACTORY, the CH2160 iModem will only communicate
with the DTE at 57.6kbps and the CH2124 at 2400bps.
However, the user may modify the DTE speed with the
appropriate
@T
®
commands. Refer to Application Note
# 155,
@T
®
Command Set Description and Usage For
CH2124/60. When the user changes the DTE
communication speed to any speed other than the
default value set of the factory, the user must ensure
that the DTE supports the speed selected. Failure to
do so could adversely affect communication with the
iModem device or, worst-case, disable communication
with the internal µP controller. Refer to Application
Note # 158, Cermetek iModem Caveats and Definitions,
for a more detailed discussion of this issue.
IMPORTANT NOTE
Cermetek recommends a minimum of 50ms inter-
character delay when sending commands to the
CH2124/60 iModem. Failure to do so could result in
unpredictable performance.
Refer to Cermetek’s High Speed Modem and FAX
Family product data sheet for a complete Description of
the internal modem’s capabilities and functions.
Serial Host Interface Buffer.
The iModem utilizes a
serial V.24 EIA 232-E 5V interface to communicate with
the internal modem and to communicate with the
internal µP.
Telephone Line Interface or DAA.
The iModem
family includes a unique low distortion DAA designed
for optimal performance over all PSTN line conditions
thereby achieving the most reliable and best
performance PSTN connections.
The CH21XX iModem family is designed to meet North
American telephone standards as set by FCC Part 68
(USA) and Industry Canada CS-03 Part I (Canada).
Each iModem product is shipped from the factory with
an FCC label indicating the FCC registration number
and ringer equivalent. The PSTN line interface is
UL1950 and CSA listed. Consequently, the iModem
family of products satisfies U.S. and Canadian
requirements, and will meet other international approval
agency requirements that specify these levels of
isolation.
IMPORTANT NOTICE
If the user wants to change the DTE/Host
communication speed to any speed other than the
factory set speed of 57.6kbps for the CH2160 or
2400bps for the CH2124, the user must first change
the DTE speed of the iModem using the appropriate
all
@T
®
commands before changing the DTE/Host
speed. Refer to Application Note # 158, Cermetek
iModem Caveats and Definitions, for a more detailed
discussion of this issue.
