Cermetek XE2422H User manual

Low-Cost, Low-Speed Surface-Mount Modem
©2009 Cermetek Microelectronics, Inc. Page 1 Document No. 607-0044 Revision A (12/11)
DESCRIPTION
The Cermetek XE2422H is a complete 2400 bps
modem in a miniature surface-mount module. It
permits the designer to easily incorporate dial-up
communications into set top box, security,
vending, or point-of-sale applications.
The XE2422H is a complete modem not just a
modem chip. Connections to the micro-controller
serial port and to the telephone line are all that is
required to design-in the XE2422H. As a
complete modem, Cermetek includes transferable
FCC Part 68 Registration. Eliminating the need
for Cermetek customers to under go FCC Part 68
testing.
The XE2422H provides the lowest total cost of
ownership. As a complete modem, it eliminates
modem design and certification costs. It reduces
assembly costs by replacing multiple components
with a single, surface-mount module. And all of
this is provide at a low per unit cost of less than
twenty dollars in volume.
FEATURES
 Small Size: 1.60” by 0.80” by 0.152”
 Data transfer rates from 300 bps to 2400 bps
• Supports V.21, V.22, V.22bis, V.23, Bell 103,
Bell 212A modem protocols
• Supports Pulse and FSK Alarm formats
 Serial data rates to 115,200 bps.
 Control and configuration via AT Commands
 3.3 and 5 volt compatible Serial Interface
 Shared Line Features prevent interference with
voice communications on an extension
telephone.
 Complete integrated DAA.
 User Transferrable FCC Part 68 Registration
 UL60950 Recognition
 Low Operating Power, 3.3 Volts, 50 mW;
 Sleep Mode with Wake-on-Ring feature
 Power Down reduces current draw to 100 A
XE2422H BLOCK DIAGRAM

Cermetek Microelectronics, Inc XE2422H Surface Mount Modem Module
©2009 Cermetek Microelectronics, Inc. Page 2 Document No. 607-0028 Revision C (10/09)
XE2422H Mechanical Specifications
E
F
FF I
A
J
HG C
D
B
INCHES MILLIMETERS
DIMENSIONS MIN TYP MAX MIN TYP MAX
A 1.595 1.600 1.605 40.51 10.64 40.77
B 0.795 0.800 0.805 20.19 20.32 20.45
C 0.147 0.152 0.157 3.73 3.86 3.99
D 0.095 0.100 0.105 2.41 2.54 2.67
E 0.055 0.060 0.065 1.40 1.52 1.65
F 0.095 0.100 0.105 2.41 2.54 2.67
G 1.045 1.050 1.055 26.54 26.67 26.80
H 0.495 0.500 0.505 12.57 12.70 12.83
I 0.995 1.000 1.005 25.27 25.40 25.53
J 0.395 0.400 0.405 10.03 10.16 10.29

Cermetek Microelectronics, Inc XE2422H Surface Mount Modem Module
©2009 Cermetek Microelectronics, Inc. Page 3 Document No. 607-0028 Revision C (10/09)
XE2422H Pin Configuration
Top View
1
2
3
4
5
6
7
13
12
11
10
9
8
Tip
Ring
/DCD
/DTR
/RI
Reserved
GND
VCC
/INT
/CTS
/RESET
RXD
TXD
Pin Descriptions
PIN NAME DESCRIPTION
1 TIP The Ring and Tip signals connect the modem to the telephone line. FCC Part 68
Rules require a 1500 volt isolation barrier between the telephone line and all other
circuits. This isolation must be preserved throughout the system.
The telephone company places a DC “Battery” voltage across Tip and Ring on public
switched telephone lines. The XE2422H operates regardless of the polarity of this
voltage. The “Battery” voltage drives up to 120 milliampere of DC loop current.
UL60950 requires minimum creepage and clearances distances between the Tip and
Ring traces and all other circuits. Clearance is the shortest distance between
conductive circuits; creepage is the distance between conductive points along the
surface
2 RING The Ring and Tip signals connect the modem to the telephone line. FCC Part 68
Rules require a 1500 volt isolation barrier between the telephone line and all other
circuits. This isolation must be preserved throughout the system.
The telephone company places a DC “Battery” voltage across Tip and Ring on public
switched telephone lines. The XE2422H operates regardless of the polarity of this
voltage. The “Battery” voltage drives up to 120 milliampere of DC loop current.
UL60950 requires minimum creepage and clearances distances between the Tip and
Ring traces and all other circuits. Clearance is the shortest distance between
conductive circuits; creepage is the distance between conductive points along the
surface.
3 /DCD /DCD is an active low output from the modem that indicates the presence of a valid
carrier signal. The SE2 register controls /DCD in the XE2422H. The default state is for
/DCD to be disabled ATSE2=04 enables /DCD.

Cermetek Microelectronics, Inc XE2422H Surface Mount Modem Module
©2009 Cermetek Microelectronics, Inc. Page 4 Document No. 607-0028 Revision C (10/09)
PIN NAME DESCRIPTION
4 /DTR /DTR is an active low input to the modem. The operation of /DTR is controlled by
register SE2 and is normally disabled. When enabled, the modem will exit data mode
and enter command mode if /DTR is removed while the modem is on-line. In Pulse
and FSK Alarm modes raising /DTR is the only was to disconnect the data link.
5 /RI The /RI signal reports on the presence of an incoming ring signal. When a ring
occurs across Tip and Ring, the /RI output goes low and toggles with the cadence of
the ring signal. /RI is controlled by register S0D bit 6. The default condition is for /RI to
be disabled.
6 RESERVED Reserved for future use
7 GROUND Ground provides the reference voltage for all host interface signals.
8 TXD TXD provides the path for transmitted data and modem commands to be passed from
the host controller to the modem. A logic high on TXD represents a “Mark” condition
and a logic low represents a “Space” condition.
9 RXD RXD provides the path for received data and modem responses to be sent from the
modem to the host controller. A logic high on RXD represents a “Mark” condition and
a logic low represents a “Space” condition.
10 /RESET /RESET is an active low input which initiates a modem hardware reset.
11 /CTS /CTS is an active low output from the modem. The modem asserts /CTS to indicate
that it can accept data from the terminal equipment on TXD.
12 /INT /INT provides an active low hardware interrupt signal from the XE2422H. The
operation of this interrupt pin is programmable using registers SE2 and S08. /INT can
be programmed to indicate Loss of Carrier, Wake-on-Ring, Loss of Loop Current, or
Shared Line Activity. Once triggered the /INT line remains active until cleared by the
AT:I command.
13 VCC VCC provides 3.3 volt power to the modem.

Cermetek Microelectronics, Inc XE2422H Surface Mount Modem Module
©2009 Cermetek Microelectronics, Inc. Page 5 Document No. 607-0028 Revision C (10/09)
XE2422H Electrical Specifications
PARAMETER MIN TYP MAX UNITS COMMENTS
VCC 3.0 3.3 3.6 VOLTS
15 mA On-Line
10 mA Sleep
ICC
1 mA Power Down
RING VOLTAGE DETECT 26 150 VRMS Type B Ringer
RING FREQUENCE DETECTED 15.3 68 Hz Type B Ringer
TELEPHONE LOOP CURRENT 16 40 120 mA
LINE IMPEDENCE 600 Ohms
DATA TRANSMIT LEVEL -9.0 dBm
DTMF TRANMIST LEVEL -2.5 0 dBm Average over a 3 second interval
Voh 2.4 Volts
Vol 0.4 Volts
Vih 2.0 5.0 Volts
ViL -0.3 0.8 VCC