Datasheet XE2486 Datasheet (XECOM)

xecom

Gnd

VCC

TXD
RXD

\DTR

\DSR

\RI
\CTS
\DCD

Serial I/O

RXA

TXA

\SLEEP

\V-D

\HS

RST

Auxilliary I/O

SPK

XE2486

8-97

Miniature 2400 bps Modem Module

Description

Xecom's XE2486 is a miniature, low cost 2400 bit
per second modem. It provides a complete
modem, including necessary memory and the
DAA in a package just 1.0 inch by 1.25 inches.
User transferable FCC Part 68 registration is
included.

The XE2486 was specifically designed to provide
OEM system designers with a quick, easy and
low-cost way to integrate a 2400 bits per second
modem. Industry standard "AT" commands
provide modem control and configuration. The
XE2486 interfaces with the system host through a
TTL level, serial interface.

Block Diagram

Features

• Supported Protocols: V.22bis, V.22, V.21, Bell
212A and 103

• "AT" commands for modem control and
configuration.

• Small Size: 1.25 inches long, 1.0 inches
wide, 0.50 inches high.

• NVRAM stores commonly dialed numbers
and custom modem configurations

• Single +5V supply

• Low power CMOS:
Operating: 200 mW (Typ.)
Sleep mode: 50 mW (Typ.)

Modem

Controller

ROM

NVRAM

Tip

Analog

Front End DAA

Ring

XECOM XE2486

XE2486 Mechanical Specifications

INCHES METRIC(MM)

PIN MIN MAX MIN MAX

A 1.240 1.260 31.50 32.00
B 0.990 1.010 25.15 25.65
C 0.490 0.510 12.45 12.95
D 0.120 0.140 3.05 3.56
E 0.090 0.110 2.29 2.79
F 0.060 0.080 1.52 2.03
G 0.090 0.110 2.29 2.79
H 0.790 0.810 20.07 20.57

Pins = 0.010 by 0.020 inches

G

H

G

D

A

Denotes Pin 1

F

E

B

C

F

Pin Configuration and Descriptions

PIN NAME DESCRIPTION

1 Ring Ring provides half the two-wire con-

nection to the telephone network,
RJ-11 Pin 4. A 1500 volt barrier
isolates Ring from all other circuits.
This isolation must be preserved
throughout the system. The battery
voltage on Ring may be positive or
negative with respect to Tip.

2 Tip Tip provides half the two-wire con-

nection to the telephone network,
RJ-11 Pin 3. A 1500 volt barrier
isolates Tip from all other circuits. This isolation must be preserved throughout
the system. The battery voltage on Tip may be positive or negative with respect
to Ring.

3,4 N/A Not used; Do not connect any circuitry to these Pins.

RING

TIP

RXA

TXA
SPK

N/C
N/C

/SLP

N/C

TXD

RXD

10 12
11

XE2486

1 22
2 21

3 19
4 18
5 17
6 16
7 15
8 14
9 13

N/C
RST

20

GND
VCC
/HS
/DCD
/CTS
/RI
/DSR
/DTR
/V-D

XECOM (2) XE2486

Pin Descriptions continued

PIN NAME DESCRIPTION

5 SPK SPK provides the audio output to a speaker. Speaker output is controlled by the

ATL and ATM commands. The input impedance to the speaker driver must be
greater than 300 ohms.

6, 7 N/C No Connection

8 /SLP This active low output indicates when the modem is in the sleep mode.
9 N/C No Connection

10 TXD TXD provides serial data input from the host. A logic high represents a "Mark"

and a low represents a "Space".

11 RXD RXD provides serial data output to the host. A logic high represents a "Mark"

and a low represents a "Space".

12 /V-D The Voice-Data ouptut can be used to drive an external relay for switching

between the modem and handset connected to the same telephone line.

13 /DTR Data Terminal Ready is an active low input to the modem. The AT&D command

sets the function of DTR.

14 /DSR Data Set Ready is an active low output from the modem. Its operation is

determined by the AT&S command.

15 /RI Ring Indicator is an active low output which marks the presence of a ring on the

line.
16 /CTS Clear to Send is not used on the XE2486; it will remain low at all times.
17 /DCD Data Carrier Detect goes low to indicate receipt of a valid incoming carrier. The

AT&C1 command enables the carrier detect function.
18 /HS This active low output indicates when the XE2486 has made a 2400 bps

connection.
19 VCC VCC provides the +5 volt power required by the modem.
20 Gnd Ground provides the common reference for the XE2486.
21 RST This active high input cause a hardware reset in the XE2486. The reset pulse

must be held high for at least 10 milliseconds to correctly reset the modem.
22 N/C No Connection

XECOM (3) XE2486

XE2486 Typical Connection Diagram

RJ11

3
4

C1

FB1
FB2

C2

Tip

Ring

SPK

/SLP

TXD
RXD

XE2486

Reset
GND

VCC
/HS
/DCD
/CTS

/RI
/DSR
/DTR

V/D

+5 Volts

16C450

UART

Note: RJ11 Pin assignments reference a 6-pin connector. Tip and Ring are the center pins of all RJ11

jacks.

Recommended Parts

Reference Designation Description Recommended Part Number

L1, L2 Ferrite Beads TDK CB30-1812

C1, C2 Capacitors Sprague 30GAT47, 470 pfd, 3000 Volts

J1 RJ11 Jack Stewart SS6446NF

XECOM (4) XE2486

AT Commands

Modes of Operation

The XE2486"AT" commands provide two
operational modes in the XE2486; Command
Mode and Data Mode.

Data Mode: The XE2486 enters data mode after
it establishes a modem link and issues a
"CONNECT" result code. In Data Mode the
modem transmits all signals on Transmit Data
(TXD) to the remote modem and puts data from
the remote modem onto Received Data (RXD).
When the modem exits data mode, it issues a "NO
CARRIER" result code.

Command Mode: The XE2486 enters command
mode on power-up, reset, a lost connection, or
escape code receipt. In command mode the
modem accepts commands from the host on
transmit data. The modem returns appropriate
responses on received data.

Command Line Format

Command lines issued to the modem follow a
strict format. The ATprefix begins each command.
The command buffer stores the command line
which is executed upon receipt of a carriage
return. Until executed, the command line can be
editied with a backspace.

Command Prefix - Each command begins with
the AT prefix. The "A" and "T" may be both upper
case or both lower case but cannot be of different
cases. The prefix identifies the speed and parity of
the host. The modem measures the width of
incoming bits to determine speed and compares
parity bits of the two characters to determine parity.

Command Line - A command line may include a
series of commands. The modem executes such
commands in the sequence they appear. A
carriage return terminates the command line and
executes the commands. Register S3 allows
selection of another character to terminate the
command line.

Command Buffer - The command buffer holds a
maximum of 40 characters, including the AT
prefix. Space inserted into the command line do
not fill space in the command buffer. Attempting to
load a longer command line causes the modem to
issue an "ERROR" result code and the commands
are not executed.

Command Line Editing - A backspace can be
used to edit the command line beforeexecution.
The backspace erases the previous character in
the command line. Register S5 allows selection of
a character other than a backspace to edit the
command line.

Re-Execute Last Command - An "A/" causes the
modem to re-execute the last command line. This
command which does not require the "AT" prefix.

Ommitted Parameters - Most commands include a
parameter which determines how the functions will
be set. When this parameter is omitted from the
command string, it is assumed to be a 0.

Escape Characters - A 3-character escape
sequence switches the modem from data to
command mode while remaining on line. The
escape character, Register S2, must be entered 3
times in succession within a 1 second guard time
to execute the escape. The default escape
sequence is "+++."

Result Codes - The modem issues a result code
after each action. Result codes may be provided
as full words, numeric codes or may be disabled all
together. Each result code ends with a carriage
return when numeric result codes are chosen.
When full word result codes are chosen, a Line
Feed and Carriage Return preceed and follow
each result code.

XECOM (5) XE2486

AT Command List

An asterisk indicates the factory default

A - Answer Command ­Bn - Select Communications Standard

n=0 Selects CCITT standards

n=1 Selects Bell standards*

D - Dial Command -

P = Pulse dial
T = Tone dial
R = Connect as an answering modem
W = Wait for dial tone
, = Pause for the duration of S8
@ = Wait for silence
! = Switch hook flash
; = Return to the command state

En - Command Echo

n=0 Do not echo commands
n=1 Enable command echo*

Hn - Switch Hook Control -

n=0 Switch hook relay closes*
n=1 The switch hook relay opens

In - Modem Identification

Ln - Speaker Volume -

n=0 Low speaker volume
n=1 Low speaker volume
n=2 Moderate speaker volume*
n=3 High speaker volume

Mn - Speaker Activity -

n=0 Speaker off
n=1 Speaker on until carrier received*
n=2 Speaker remains on
n=3 Speaker on after dialing until carrier is

detected.

On - On Line

n=0 Return On Line with no retrain*
n=1 Initiate retrain while returning On line.

Qn - Responses

n=0 Send responses *
n=1 No Responses

Sr? - Interogate Register -

Sr=n - Set Register Value -

Xn - Result Code Set -

n=0 Responses 0-4*
n=1 Responses 0-5 & 10
n=2 Responses 0-6 & 10
n=3 Responses 0-5, 7 & 10
n=4 Responses 0-7 & 10

Z - Reset ­&Cn - DCD Operation

n=0 DCD is forced active*
n=1 DCD indicates a valid carrier signal

&Dn - DTR

n=0 DTR is ignored by the modem*
n=2 Modem disconnects if the host revokes

DTR.

n=3 The modem performs a soft reset when

DTR is revoked.

&F - Revert to Factory Defaults
&Ln - Line Type

n=0 Modem operates on dial-up lines*
n=1 Modem operates on leased lines

&Qn - Communications Format

n=0 Sets the modem for normal, unbuffered

operation.

&Tn - Test Modes

n=0 Exit test mode
n=1 Local analog loopback
n=3 Initiate local digital loopback
n=4 Respond to remote loop request*
n=5 Deny remote loop request
n=6 Intiate a Remote Digital loopback
n=7 Remote digital loopback w self-test
n=8 Local analog loopback w self-test

&V - View Active Profile ­&Wn - Store Profile -

n=0 Stores the current configuration in

memory location 0.

n=1 Stores the current configuration in

memory location 1.

&Yn - Recall Profile

n=0 Use memory location 0.
n=1 Use memory location 1.

Vn - Result Codes -

n=0 Numeric Result Codes
n=1 English Word Result Codes*

&Zn=X- Store Number

XECOM (6) XE2486

S-Register Summary

REG. RANGE/UNITS DESCRIPTION DEFAULT

S0 0-255/rings Number of rings to answer on 000
S1 0-255/rings Count number of incoming rings 000
S2 0-127/ASCII Escape character 043
S3 0-127/ASCII Carriage return character 013
S4 0-127/ASCII Line feed character 010
S5 0-32,127/ASCII Backspace character 008
S6 2-255/sec Dial tone wait time 002
S7 1-60/sec Wait time for remote carrier 030
S8 0-255/sec Comma pause time 002

S9 1-255/0.1 sec Carrier detect response time 006
S10 1-255/0.1 sec Delay from loss of carrier to hang up 014
S14 Bit Mapped E,Q,V,T,P,D,A,R accept/ignore 170
S16 Bit Mapped Modem loopback tests 000
S18 0-255/sec Modem test timer 000
S21 Bit Mapped J, &R, &D, &C, &S, Y 000
S22 Bit Mapped L, M, X, &P, &T4, &T5, DTE speed and parity 118
S23 Bit Mapped &T4,&T5, DTE speed, parity 007
S27 Bit Mapped &Q, &L, &X, B commands 064

Result Code Summary

DIGIT CODE WORD CODE MEANING

0 OK Successfully executed command line
1 CONNECT 300 bps connection established
2 RING Ring signal detected
3 NO CARRIER Carrier not detected within Register S7 detect time
4 ErroR Error found in command line; returns to command line
5 Connect 1200 1200 bps connection established
6 No dial tone No dial tone detected within 5 Sec. after going off-hook
7 Busy Busy signal detected after automatically dialing a call
8 No answer Five seconds of silence was not detected when using the @ command in

the Dial command line

10 Connect 2400 Connection established at 2400 bps

XECOM (7) XE2486

Electrical Specifications

Absolute MAaximum Ratings*

SUPPLY VOLTAGE - Vcc +6.5 Volts

DC INPUT VOLTAGE -0.6 Volts to +6.5 Volts

STORAGE TEMPERATURE RANGE -25° C TO +100° C

LEAD TEMPERATURE (Soldering, 2 sec per wave) 260° C

OPERATING TEMPERATURE RANGE 0 TO 70° C

*Exceeding these values may result in permanent damage to the device.

Telephone Interface Specifications

PARAMETER MIN TYP MAX UNIT

Telephone Line Impedance Match 600 ohms
Ring Detect Sensitivity (on hook, Type B ringer) 38 Vrms
Telephone Loop Current 20 100 mA

Power Supply Characteristics(TA = 0 - 70°C, Vcc = 5v ±5%)

Symbol Parameter Min Typ Max Units Comments

Vcc Supply Voltage 4.75 5.0 5.25 V
Icc Vcc Supply Current 40 mA All outputs Disconnected
Iccpd Power Down Current 10 mA

Power Management:

detected on the RXD, DTR, or RI lines the modem will automatically go into a smart power down mode. In this mode
power consumption is typically less than 50 milliwatts.

The XE2486 has an integrated, advanced power management capability. If no activity is

XECOM (8) XE2486

FCC Instructions

This product complies with Part 68 of the FCC Rules. With each device shipped, there is a label which
contains, among other information, the FCC Registration Number and Ringer Equivalence Number
(REN) for this product. You must, upon request, provide this information to your telephone company.

The mounting of this device in the final assembly must be made in such a manner as to preserve the high
voltage protection between the TIP/RING and the rest of the system. Typically, this may be accomplished
by maintaining a minimum spacing .100 mils between the TIP/RING Traces to the RJ-11C Jack and low
voltage portion of the system. No additional circuitry may be attached between TIP/RING and the
telephone line connection, unless specifically allowed in the rules.

The REN helps determine the number of devices you may connect to a telephone line and still have all of
these devices ring when the number is called. In most, but not all areas, the sum of the RENs of all
devices connected to one line should not exceed five (5.0). To be certain of the number of devices you
may connect to the line, as determined by the REN, you should contact the local telephone company to
determine the maximum REN for your calling area.

If your system causes harm to the telephone network, the telephone company may discontinue service
temporarily. If possible, they will notify you in advance. If advance notification is not practical, you will be
notified as soon as possible.

Your telephone company may make changes in its facilities, equipment, operations or procedures that
could affect proper functioning of your equipment. If they do, you will be notified in advance to give you
an opportunity to maintain uninterrupted telephone service.

If you experience trouble with this device, please contact XECOM at [phone] for information on
obtaining service or repairs. The telephone company may ask you to disconnect this device from the
network until the problem has been corrected or until you are sure that the device is not malfunctioning.

The device may not be used on coin service lines provided by the telephone company (this does not
apply to private coin telephone applications which use standard telephone lines). Connection to party
lines is subject to state tariffs.

XECOM (9) XE2486

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
provided 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
reasonably expected to cause failure of the life support device or system, or to affect its safety or effectiveness.

Copyright, Xecom © 1997
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 trademarks and/or registered trademarks of their respective companies.

X e com Incorporated

xecom

374 Turquoise Str eet , Mi lpitas, CA 95035
Ph:408-945-6640 Fax:4 08-94 2 - 1 346 E-Mail: [e-mail]

XECOM XE2486