Cermetek Microelectronics, Inc.
High Speed Internet Modem Family
2005 Cermetek Microelectronics, Inc.
Page 11
Document No. 607-0017-01 Revision A (05/05)
Table 2. iModem Family Pin Description.
PIN NAME I/O
FUNCTION
1
RING
I/O
Directly connects to the telephone line’s Ring lead through a user supplied RJ-11C jack.
2
TIP
I/O
Directly connects to the telephone line’s TIP lead through a user supplied RJ-11C jack.
3
NC
---
NO CONECTION
4
NC
---
NO CONECTION
5
SPK
O
SPEAKER. Audio output for speaker. See speaker control diagram.
6
SEND
I
SEND EMAIL. Not Currently Supported. No Connect.
7
IN 1
I
Input. Not Currently Supported. No Connect.
8
SENT
O
EMAIL SENT. Not Currently Supported. No Connect.
9
IN 2
I
Input. Not Currently Supported. No Connect.
10
TXD
I
TRANSMIT DATA. Serial transmit data input. Marking, or a binary 1 condition is indicated
by a HIGH.
11
RXD
O
RECEIVE DATA. Serial Receive data output. Received marking or a binary 1 condition is
indicated by a HIGH.
12
NC
---
NO CONECTION
13
DTR
I
DATA TERMINAL READY INPUT. Active LOW. Switching off DTR can either return
modem to command state, disconnect phone call, or reset modem. DTR should be set
LOW when not in use.
14
DSR
O
DATA SET READY. LOW indicates handshaking with a remote modem in progress,
and/or the data carrier of a remote modem has been detected.
15
RI
O
RING INDICATION. This signal follows the frequency of the ringing signal and is normally
about 20 to 40 Hz for 2 seconds on with 4 second off.
16
CTS
O
CLEAR-TO-SEND. Output always LOW. Reserved for flow controls with FAX option. Not
active, let float.
17
DCD
O
DATA CARRIER DETECT. LOW indicates a data carrier from a remote modem has been
detected. Must enable with
AT&C1
Hayes command.
18
NC
---
NO CONECTION
19
VCC
---
DC SUPPLY. 5V ± 5% required.
20
GND
---
GROUND. Note: Noise should be less than 25mV peak to peak.
21
RST
I
RESET. Active HIGH. This input must be asserted HIGH for at least 10ms to reset the
modem. RESET is then returned to LOW for normal operation. If no system reset is
available, let this pin float to enable internal reset.
22
RTS
I
REQUEST TO SEND. Active Low. Used for flow control. Should be tied Low when using
SEND pin and when using
@T
commands for CH2160 only. DO NOT CONNECT for
CH2124.
