Cermetek Microelectronics, Inc.
High Speed Internet Modem Family
2005 Cermetek Microelectronics, Inc.
Page 4
Document No. 607-0017 Revision I1 (05/05)
Figure 2. Functional Block Diagram of Cermetek CH2124/60 iModem Products.
DESCRIPTION OF FUNCTIONAL BLOCKS AND
DISCUSSION OF BASIC OPERATIONS
Each CH21XX iModem product consists of the following
functional blocks:
1. µP controller with Network Protocols and Flash
ROM.
2. Serial interface buffer.
3. Input/Output interface circuitry.
4. Internal modem (V.90 or V.22bis).
5. Modem
interface
circuitry.
6. DAA (Data Access Arrangement) PSTN interface.
Figure 2 contains a schematic drawing illustrating the
interconnectivity of the various functional blocks
comprising the CH21XX iModem products.
Each iModem performs the following internet
connectivity functions automatically:
1. Dials local POP and Connects to ISP.
2. Authenticates user ID and logs onto the internet.
3. Sends (or Retrieves) email to (from) the server
address/name specified using the ISP’s SMTP
(POP3) Mail Server.
4. Terminates ISP session after all data is sent (or
retrieved).
5. The CH2124/60 sends an ASCII MESSAGE
ACCEPTED activity response message and sends
a TTL LOW Pulse to Pin 8 indicating that the ISP
Mail Server has accepted the email message.
Control of the internet capabilities of the iModem can be
either event driven or initiated and controlled by a
system level host processor. Refer to Table 3 for a
complete set of pin descriptions.
When not utilized in the internet connectivity role, the
iModem will function as a standard analog modem.
KEY FEATURE
The user has complete control of the level of
autonomy the iModem exercises in the user’s
application. This is a unique feature of Cermetek’s
iModem products.
µP Controller.
The µP controller performs the required
internet operations by interpreting each specific
@T
®
command and executing the appropriate internet
commands. The necessary internet protocol firmware
is resident in flash ROM. The
@T
®
commands function
as an extension to the industry standard Hayes AT
command set.
PSTN
Input 1
Input 2
SEND EMAIL
CONTROL
PIN
INPUT
SENSE
AND
OUTPUT
PINS
Interface
Circuitry
SERIAL
INTERFACE
V-24
EIA-232-E or
UART
MODEM
V.90 (CH2160/65)
V.22bis (CH2124)
MODEM INTERFACE
DAA
CH21XX
RXD
RTS
DCD
DSR
RI
CTS
TXD
DTR
TIP
Ring
EMAIL
ACCEPTED
INDICATOR
PIN
Flash ROM
32Kx8
Network
Protocol
SMTP
TCP
IP
PPP
POP 3
µP
RST
SPK
+5V
GND
