XECOM XE1214B5 Datasheet

xecom

XE1214B5

06-24-93

1200bps Component Modem

D e s c r i p t i o n

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.

Block Diagram

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

PIN CONFIGURATION

1 • 40

AA\ HS\ CD\

DTR\

RXDC

N/C

EHC

RXDM

TXD

CLKOUT

AADIS\

OH\

2 39 3 38 4 37 5 6 7 8 9 10 11

RI\

12 13

VCC GND N/C AUDIO

17 24

TIP

18 23

N/C

19 22

N/C

20 21

RING

N/C N/C N/C 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,

2 \HS O This output, when low, indicates that the modem is in the high speed

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

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

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

6 N/C --- No Connection.

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.

(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.

connection is broken, or never established| \CD remains high. For display purposes, this output may drive an external LED through a 330 ohm resistor.

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.

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.

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

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

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.

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 T X D 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 " m a r k " .

1 0 C L K O U T 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.

1 1 \ R I 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 o n l y .

1 2 \ A A D I S 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.

1 3 \ O H 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. 1 4 - 1 6 N / C - - - No connection. 1 7 , 2 0 T I P - R I N G - - - 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. 1 8 , 1 9 N / C - - - No connection. 2 1 - 2 4 N / C - - - No connection.

3 7 A U D I O 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.

3 8 N / C - - - No connection. 3 9 G N D - - - Ground (0 volts). 4 0 V C C - - - Positive supply voltage (+5 volts).

XE1214B5 3\XECOM

S-Register Description

S0 0-255/rings 1 Number of rings before the XE1214B5 answers the call. With

S1 0-255/rings 0 Number of rings detected. S1 is cleared if no ring occurs

S2 0-127/ASCII 43 ASCII value for the escape code. Values greater than 127 are

S3 0-127/ASCII 13 ASCII value for carriage return. The character in S3 is used

S4 0-127/ASCII 10 ASCII value for line feed. The XE1214B5 sends a line feed

S5 0-32, 127/ASCII 8 ASCII value for backspace. This character is both the

S6 2-255/sec. 2 Waiting time before dialing when X0, X1 or X3 is enabled.

S7 1-255/sec. 30 The time the XE1214B5 waits for carrier signal detection from

S8 0-255/sec. 2 Pause time for each comma. The comma is used during

S9 1-255/0.1 sec. 6 The time required for the carrier signal from a remote modem

S10 1-255/0.1 sec. 14 The time between the loss of carrier from a remote modem

S0=0, the XE1214B5 does not answer the call. With S0=5, the XE1214B5 answers the call on the fifth ring.

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

not accepted, but do disable escape code operation.

for both the command line and the result code terminators.

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.

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.

Values greater than 2 seconds may be necessary if trouble is encountered getting dial tones.

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.

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.

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.

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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