XECOM XE1214B5 Datasheet

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xecom

XE1214B5

06-24-93

1200bps Component Modem

Description

The XE1214B5 is a complete, self contained 1200/300 bps modem in small, component form. It contains all circuitry necessary for a complete modem, including an internal, FCC Registered, Data Access Arrangement (DAA) for direct connection to the telephone line, and a serial TTL interface. With the addition of line driver and receiver ICs (such as the MC1488 and MC1489), this serial interface may be easily converted to a full RS232C serial interface.

The XE1214B5 uses the industry standard "AT" commands. This allows the XE1214B5 to operate with most communications software. It supports full duplex, 1200/300 bps, data transfer with either Bell 212A/103 or CCITT V.22/V.21 modulation. The XE1214B5 includes the capability to monitor call progressand generate DTMF and guard tones required for CCITT V.22/V.21 communication. It operates in the asynchronous mode and provides analog loopback, digital loopback and remote digital loopback functions for testing purposes.

Features

Small Size -2.28" x 1.0" x 0.5"

FCC Part 68 Registered

Fully Bell 212A/103 and CCITT V.22/V.21 Compatible

Complete Industry Standard "AT" Command Set

TTL Serial Interface

Call Progress Monitoring

DTMF and Pulse Dialing

Software Controlled Audio Output

UL Recognized Component

CSA Recognized Component

+5 Volt Power Only

 

 

 

 

 

 

 

 

 

 

 

 

 

Block Diagram

 

 

PIN CONFIGURATION

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AA\

 

 

1 •

40

 

 

VCC

 

 

 

 

 

HS\

 

 

2

39

 

 

GND

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CD\

 

 

3

38

 

 

N/C

 

 

 

 

 

 

 

 

 

 

 

 

 

 

DTR\

 

 

4

37

 

 

AUDIO

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

RXDC

 

 

5

 

 

 

 

 

 

 

 

 

N/C

 

 

6

 

 

 

 

 

 

 

 

 

EHC

 

 

7

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

RXDM

 

 

8

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TXD

 

 

9

 

 

 

 

 

 

 

 

 

CLKOUT

 

 

10

 

 

 

 

 

 

 

 

 

RI\

 

 

11

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

AADIS\

 

 

12

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

OH\

 

 

13

 

 

 

 

 

 

 

 

 

TIP

 

 

17

24

 

 

N/C

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

N/C

 

 

18

23

 

 

N/C

 

 

 

 

 

N/C

 

 

19

22

 

 

N/C

 

 

 

 

 

RING

 

 

20

21

 

 

N/C

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Pin Descriptions

PIN

NAME

I/O

DESCRIPTION

 

 

 

 

1

AA

O

AA goes low when the XE1214B5 is set in the auto-answer mode,

 

 

 

either by switch input AA DIS (pin 12) or register S0. If the XE1214B5

 

 

 

is not set to automatically answer (pin 12 held low, or S0 = 0), AAl

 

 

 

follows the incoming ring signal, going low for the 4 sec interval

 

 

 

between rings. For display purposes, this output may be used to drive

 

 

 

an external LED through a 330 ohm resistor.

2

\HS

O

This output, when low, indicates that the modem is in the high speed

 

 

 

(1200 bps) mode. When high, it indicates that the modem is in the low

 

 

 

speed (300 bps) mode. For display purposes, this output may be used

 

 

 

to drive an external LED through a 330 ohm resistor.

3

\CD

O

\CD indicates detection of a remote modem by going low. If the

 

 

 

connection is broken, or never established| \CD remains high. For

 

 

 

display purposes, this output may drive an external LED through a 330

 

 

 

ohm resistor.

4

\DTR

I

A low on \DTRallows the XE1214B5toll execute data call commands. If

 

 

 

this input is driven high during a data call, the XE1214B5 terminate the

 

 

 

data call, hang up the phone line and return to the command state.

5

RXDC

O

The XE1214B5 internal controller (see block diagram) uses RXDC to

 

 

 

transfer serial data in an asynchronous start/stop format at the data rate

 

 

 

selected by the terminal. This data is either the echo of commands

 

 

 

received from the terminal, or result codes generated by the controller

 

 

 

during processing of commands. It is normally high, and should be

 

 

 

"AND"ed with RXDM (pin 8) to form the received data to the terminal.

6

N/C

---

No Connection.

7

EHC

O

External Handset Control, when activated by the H1 Command, is used

 

 

 

to control an additional relay to allow an independent handset to be

 

 

 

connected to the telephone line. During data transmission, when the

 

 

 

relay in the internal DAA is closed (off-hook), this output is low. When

 

 

 

the internal relay is open (on-hook), this output is high,and may be used

 

 

 

to control an external relay to connect a telephone handset to the line.

8

RXDM

O

The internal modem processor of the XE1214B5B5 (see block diagram)

 

 

 

demodulates the received carrier and outputs data on this pin. A logic

 

 

 

low level is "space" and a logic high is "mark". This output is normally

 

 

 

high, and should be "AND"ed with RXDC (pin 5) to form the received

 

 

 

data signal to the terminal.

 

 

 

 

2/XECOM

XE1214B5

Pin Descriptions

PIN

NAME

I/O

DESCRIPTION

9

TXD

I

This is the input for data to be transmitted. The internal controller of

 

 

 

the XE1214B5 receives command data from the terminal on this input

 

 

 

while the internal modem processor receives data from the terminal

 

 

 

on this input for modulation. A logic low is "space" and a logic high is

 

 

 

"mark".

10

CLKOUT

O

The buffered internal clock signal is output on this pin. Its frequency

 

 

 

is 7.3728 MHz and it can drive one LS TTL load.

11

\RI

O

Ring Indicator. A low level on this status line indicates the ring portion

 

 

 

of the ring cycle. This line is normally used for test/status purposes

 

 

 

only.

12

\AADIS

I

When this input is held low, the XE1214B5 will not answer incoming

 

 

 

calls. When held high or left open, the XE1214B5 will automatically

 

 

 

answer incoming calls on the first ring. This function may also be

 

 

 

enabled/disabled by writing to the S0 register.

13

\OH

O

Off Hook status monitor. This status line allows the user to monitor

 

 

 

the status of the hookswitch relay in the internal DAA (see block

 

 

 

diagram). When the signal on OH is low, the internal relay is closed

 

 

 

and the XE1214B5 is connected to the phone line. During rotary

 

 

 

dialing, this pin is pulsed at a rate of 10 pps with appropriate

 

 

 

Make/Break ratio depending on the 212A or V.22 mode selected.

14-16

N/C

---

No connection.

17,20

TIP-RING

---

These pins are for the TIP and RING connections to the telephone

 

 

 

line from the internal DAA. In order to preserve the high voltage

 

 

 

isolation provided by the DAA, traces from these pins to the RJ11C

 

 

 

Jack should have a minimum spacing of 150 mils between them and

 

 

 

any other traces on the PC board.

18,19

N/C

---

No connection.

21-24

N/C

---

No connection.

37

AUDIO

O

The output of the internal hybrid 2-4 wire converter is brought out on

 

 

 

this pin through an internally programmable attenuator. The

 

 

 

attenuation level may be set by the ATL command.

38

N/C

---

No connection.

39

GND

---

Ground (0 volts).

40

VCC

---

Positive supply voltage (+5 volts).

 

 

 

 

XE1214B5

3\XECOM

S-Register Description

Register

Range/Units

Default

Description

S0

0-255/rings

1

Number of rings before the XE1214B5 answers the call. With

 

 

 

S0=0, the XE1214B5 does not answer the call. With S0=5,

 

 

 

the XE1214B5 answers the call on the fifth ring.

S1

0-255/rings

0

Number of rings detected. S1 is cleared if no ring occurs

 

 

 

within 8 seconds. S1 operates only if S0 is not zero.

S2

0-127/ASCII

43

ASCII value for the escape code. Values greater than 127 are

 

 

 

not accepted, but do disable escape code operation.

S3

0-127/ASCII

13

ASCII value for carriage return. The character in S3 is used

 

 

 

for both the command line and the result code terminators.

S4

0-127/ASCII

10

ASCII value for line feed. The XE1214B5 sends a line feed

 

 

 

after it sends a carriage return only when English word result

 

 

 

codes have been selected (V1). If a line feed is not needed, it

 

 

 

can be set to a null. But this function cannot be disabled.

S5

0-32, 127/ASCII

8

ASCII value for backspace. This character is both the

 

 

 

backspace key and the character echoed to move the cursor

 

 

 

back one position. The values between 33 and 126, the range

 

 

 

of printable ASCII characters are not accepted.

S6

2-255/sec.

2

Waiting time before dialing when X0, X1 or X3 is enabled.

 

 

 

Values greater than 2 seconds may be necessary if trouble

 

 

 

is encountered getting dial tones.

S7

1-255/sec.

30

The time the XE1214B5 waits for carrier signal detection from

 

 

 

remote modem before hanging up. If the XE1214B5 does not

 

 

 

detect a carrier signal within that time, it hangs up and a NO

 

 

 

CARRIER result code is displayed. If it does, a CONNECT

 

 

 

result code (or (CONNECT 1200 when X1, X2, X3 or X4 is

 

 

 

enabled) is displayed and the XE1214B5 goes on line. Also

 

 

 

used to control time-out of W command.

S8

0-255/sec.

2

Pause time for each comma. The comma is used during

 

 

 

dialing when it is necessary to dial out of a PBX and wait for a

 

 

 

second dial tone. Two seconds is usually enough, however

 

 

 

the default may be changed or multiple commas may be used

 

 

 

for longer time delays.

S9

1-255/0.1 sec.

6

The time required for the carrier signal from a remote modem

 

 

 

must be present for the XE1214B5 to recognize it as a carrier

 

 

 

and signal a carrier detection. This feature prevents the

 

 

 

XE1214B5 from mistaking a carrier signal for a ring or busy

 

 

 

signal. The Units are in tenths of seconds.

S10

1-255/0.1 sec.

14

The time between the loss of carrier from a remote modem

 

 

 

and hangup. With S10 equal to 255, XE1214B5 acts as if

 

 

 

carrier is always present. If S10 is smaller than S9,

 

 

 

XE1214B5 disconnects for short loss of carrier. This is

 

 

 

because S10 will time out before the carrier detect response

 

 

 

time expires. The Units are in tenths of seconds.

4/XEC0M

XE1214B5

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