Miniature Telephone Line Interface Module for CTI Applications
The XE0055CS2 is an extremely compact, high-perfor- * Small Size: 2.0" long by 0.5" wide by 0.27" thick;
mance telephone interface module. The XE0055CS2
meets the technical requirements for V.34bis operation
* V.34bis compatible for data transfer at speeds up to
yet fills less than one quarter cubic inch of space. The
XE0055CS2 complies with FCC Part 68 Rules simpli-
* FCC Part 68 Compliant;
fying certification of the completed system.
* Integrated Ring Detect Circuit;
The XE0055CS2 is a low power design operating from
a single +5 volt power supply. As with all Xecom tele-
* Provides an on-hook signal path for monitoring the
phone interface modules, internal ring indication and
Caller ID Signal
switch hook are provided to establish the telephone line
* Integrated Connect Detect circuit continually monitors
the availbility of the local telephone line
The XE0055CS2 also includes advanced features for
* Single 5 Volt Power Supply
Computer Telephone Integration (CTI) applications.
The XE0055CS2 incorporates Caller ID access and a
* Integrated Solid-State Switch Hook
continuous Connect Detect monitor. Connect Detect
reports the current availability of the local telephone
* Provides a 1500 volt isolation barrier between the
line. With these features the host can screen incoming
Telephone Line and all other circuits
calls and intiate outgoing calls only when the line is
XE0055CS2 Block Diagram
XE0055CS2 Mechanical Specifications
Pin Size: 0.025" by 0.025"
Recommended hole size: 0.056"
ABSOLUTE MAXIMUM RATINGS
-25 C to +85 C
Operating Temperature Range
0 C to +70 C
Maximum Lead Temperature
(soldering 2 seconds per wave)
Note: The XE0204 is available with an extended operating temperature range of -40C to +85C. To specify the
version with the extended operating temperature range order XE0204-ITR.
XE0055CS2 Pin Configuration
OH T1 Gnd Vcc T2
XE0055CS2 Pin Descriptions
Ring is one of two signals which form the telephone network connection (RJ11 Pin
4). This device is not sensitive to the polarity of the battery voltage on the telephone
line. Ring has 1500 volts isolation from the rest of the circuitry. This isolation must
be preserved throughout the system.
Tip provides the second connection to the telephone network (RJ11 Pin 3). Tip has
1500 volts isolation from the rest of the circuitry. This isolation must be preserved
throughout the system.
Hook-switch relay control input. A high on OH closes the internal relay and con-
nects the equipment to the telephone line.
T1 connects directly to the secondary side of the XE0055CS2 telephone line trans-
This pin is used as common reference for all of the control signals in the
XE0055CS2. Signals on T1 and T2 are not referenced to ground.
VCC provides the power source for the hook-switch control. The XE0055CS2 will
operate with VCC equal to either 3.3 or 5 volts
T2 connects directly to the secondary side of the telephone line transformer of the
Ring Indicate, output, active low, TTL, RI provides a half-wave representation of the
Ring appearing on the telephone line. An external pull-up resistor is required to cor-
rectly bias the ring indicate output.
The Connect Detect output indicates the status of the local telephone line. A high on
CD indicates that the local telephone line is connected and is not currently in use. A
low on CD indicates that the local telephone line is either disconnected from the
XE0055CS2 or is being used by some other telephone equipment.
XE0055CS2 Electrical Specification (Vcc=+5v ±10%, Ta=0 to 70 deg C)
Power Supply Current
Off Hook, 5.0 Volts
Transmit Insertion loss
600 Ohm Impedence, 1000 Hz
Receive Insertion loss
600 Ohm Impedance, 1000 Hz
At 1000 Hz, Rm 340 ohms
Coupler Match Input
Input impedance to T1 & T2
Ring Detect Sensitivity
Min. AC voltage between Tip & Ring
Type B ringer
Ring Detect Peak Current
Ringing Voltage of 40 Vrms applied across
Tip and Ring
Ring Detect Idle Current
No Ringing Voltage present
Ring Indicate Output
Ring Voltage present on Tip and Ring
Hook Switch Control
Hook Switch Control
Off-Hook current draw from the
Total Harmonic Distortion
At 1800 Hz, -9 dBm signal level
XE0055CS2 Typical Connection Diagram
o Pin 1 Ring
o Pin 2 Tip
o Pin 3 OH
o Pin 4 T1
o Pin 5 Gnd
o Pin 6 VCC
o Pin 7 T2
o Pin 8 /RI
To Embedded System Host
o Pin 9 CD
FB1 and FB2 are ferrite beads. They work in conjunction with Capacitors C1 and C2 to eliminate EMI from the
telephone cable. Xecom recommends a TDK CB30-1812 surface mount ferrite bead because it provides over 100
ohms impedance at 100 MHz.
C1 and C2 ground any EMI signal present on Tip and Ring. Xecom recommends a Sprague 30GAT47 capacitor.
This is a 470 pFd capacitor rated for 3000 Volts. The high voltage rating is required to maintian the required
isolation barrier between the telephone line and ground.
RV1 is a solid-state protection device to reduce the likelihood of damage due to lightning strikes. RV1 works in
conjunction with the two 10 ohm resistors to protect the XE0055CS2 circuitry. Xecom recommends the Teccor
P3100 Sidactor for this function. Its typical breakover voltage of 310 volts prevents the XE0055CS2 from being
exposed to voltage surges while being rated high enough to prevent being triggered by an incoming Ring signal.
FCC Part 68 Instructions
When developing a product to be connected to the telephone line, it is necessary to use a circuit known as a Data
Access Arrangement (DAA) approved by the appropriate governmental agency. In the US this agency is the Federal
Communications Commission (FCC), while in Canada it is Industry Canada (IC). These agencies test and approve the
product to ensure that it meets their specifications, thereby protecting the telephone system from damage and
protecting the user from high voltage transients (such as lightning strikes) which may come down the telephone line.
The XE0055CS2 has been designed to meet all FCC Part 68 requirements for hazardous voltage, line impedance and
leakage current. If the system transmits data, synthesized voice, or DTMF tones on the telephone line, the user must
certify that the signals transmitted meet basic FCC requirements for maximum transmission levels, out of band energy
and billing delay. Full details may be obtained from the FCC under Part 68 of the FCC Rules and Regulations, or in
Title 47 of the Code of Federal Regulations, however the basic requirements are as follows:
1. Maximum Transmit Level
For the normal “permissive” (standard) telephone line, equipment which transmits data (such as a modem) must not
exceed a transmission level of -9 dBm.
2. Out of Band Energy
Data equipment must not transmit “out of band” energy on the telephone line which exceeds the following limits:
3. DTMF Transmission Level
If the system is capable of DTMF dialing, the maximum DTMF transmission level must be less than 0 dBm averaged
over a 3 second interval.
4. Billing Delay
A delay of 2 seconds or greater is required after the time the XE0055CS2 is taken “off hook” and before any
information is transmitted. This is required to ensure that billing information may be exchanged between telephone
company central offices without interference.
The user of the XE0055CS2 must certify to the FCC that the final system meets the requirements of Part 68 which
include the criteria above as well as the high voltage protection provided by the XE0055CS2. This is generally
accomplished through an independent testing lab which tests the System and submits the proper paperwork to the FCC
for approval. Since the XE0055CS2 already complies with FCC Part 68 rules, this is a relatively simple process.
Terms of Sale
Devices sold by XECOM are covered by the warranty provisions appearing in its Terms of Sale only. XECOM
makes no warranty, express, statutory, implied, or by description regarding the information set forth herein, or
regarding the freedom of the described devices from patent infringement. XECOM makes no warranty of
merchantability or fitness for any purposes. XECOM reserves the right to discontinue production and change
specifications and prices at any time and without notice. This product is intended for use in normal commercial
applications. Applications requiring extended temperature range, unusual environmental requirements, or high
reliability applications, such as military, medical life-support or life-sustaining equipment, are specifically not
recommended without additional processing and authorization by XECOM for such application.
Xecom assumes no responsibility for the use of any circuitry other than circuitry embodied in a Xecom product.
No other circuits, patents, or licenses are implied.
Life Support Policy
Xecom's products are not authorized for use as Critical Components in Life Support Devices or Systems.
Life Support Devices or Systems are devices or systems which, (a) are intended for surgical implant into the body,
or (b) support or sustain life, and whose failure to perform, when properly used in accordance with instructions pro-
vided in the labeling, can be reasonably expected to result in significant injury to the user.
A Critical Component is any component of a life support device or system whose failure to perform can be rea-
sonably expected to cause failure of the life support device or system, or to affect its safety or effectiveness.
Copyright, Xecom © 1999
While Xecom, Inc. has made every effort to ensure that the information presented here is accurate, Xecom will not
be liable for any damages arising from errors or omission of fact. Xecom reserves the right to modify specifications
and/or prices without notice. Product mentioned herein are used for identification purposes only and may be trade-
marks and/or registered trademarks of their respective companies.
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