XE1401F Просмотр технического описания (PDF) - Xecom

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XE1401F

Multi-National 14,400 BPS Embeddable Modem

Xecom 

XE1401 Pin Descriptions

PIN NAME DESCRIPTION

1 RESET

Hardware reset pin, Input, active High, TTL. A high on Pin 1 initiates a hardware reset. An

external reset is not required or recommended. The Reset pulse must be a minimum of 100

milliseconds long.

2 N/C

No Internal Connection

3 RXD

Received Data, Output, TTL. Serial data output to the host. A logic "High" on RXD rep-

resents a "mark" and a logic "Low" represents a "space".

9 \DTR

Data Terminal Ready, Input, active Low, TTL. The "AT&D" command sets the function of

\DTR. The default, AT&D2, requires the host to assert \DTR to permit a modem link. The

modem drops the call in progress if \DTR is revoked and will not connect until \DTR is re-

asserted.

10 \LCS

Loop Current Sense, active Low Input, TTL. A low on \LCS tells the modem that loop

current is flowing through Tip and Ring. This feature is used only in the XE1401B version.

11 \CTS

Clear to Send, Output, active Low, TTL/CMOS. \CTS is used as a Flow Control output

from the modem. The modem revokes \CTS with hardware flow control active to signal the

host that the modem's input buffer is full. The modem reasserts \CTS when the buffer can

accept more data without a buffer overflow.

12 OH

Off-Hook, Output, active High. OH indicates the modem's hookswitch relay is closed.

Hookswitch closure connects the modem to the telephone line.

13 TXD

Transmit Data, Input, TTL. Serial data input from the host. A logic "High" represents a

"mark" and a Low represents a"space", TTL.

14 \RTS

Request to Send, input, active LOW, TTL. The XE1401 uses \RTS for hardware flow con-

trol. When \RTS is revoked and hardware flow control is enabled, the modem will not place

data on RXD.

15 NC

No Internal Connection

16 \RI

Ring Indicator, Output, active Low, TTL. When low indicates the modem is receiving a ring

signal.

18 TIP

Tip connection to the phone line (RJ11 pin3) from the internal DAA. The XE1401 is not

sensitive to the battery voltage polarity across Tip and Ring.

20 RING Ring connection to the phone line (RJ11 pin4) from the internal DAA.

21 GND Ground (0 volts)

22 AMP

Audio Output function is set by L & M commands and the value in register S22. This output

can drive a minimum load of 300 ohms.

XECOM

(3)

XE1401

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