XRT4500 Datasheet, PDF (22/99 Pages) Exar Corporation – MULTIPROTOCOL SERIAL NETWORK INTERFACE IC

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PIN DESCRIPTIONS (CONT.)
XRT4500
MULTIPROTOCOL SERIAL NETWORK INTERFACE IC
REV. 1.0.7
PIN
Signal
#
60
TX1D
61
CM_TX1
62
TX1B
DTE
MODE
D_TXD
DCE TYPE FUNCTION
MODE
D_RXD
I Transmitter 1 – Digital Data Input from Terminal Equipment.
The exact role that this input pin plays depends upon whether
the XRT4500 is operating in the DTE or DCE Modes.
DTE Mode – TXD (Transmit Data) Input:
The DTE Terminal Equipment is expected to apply the TXD
(Transmit Data) to this input pin.
The XRT4500 will convert this binary data stream into either the
V.35, V.11, or V.28 format and will output this data via the TX1A
and TX1B output pin.
DCE Mode – RXD (Receive Data) Input:
The DCE Terminal Equipment is expected to apply the RXD
(Receive Data) to this input pin.
TXDB RXDB
The XRT4500 will convert this binary data stream into either the
V.35, V.11 or V.28 format and will output this data via the TX1A
and TX1B output pins.
O AC GND- Transmitter 1 Output Termination center tap in V.35
Mode. Connect a 0.1µF capacitor to ground.
O Transmitter 1 – Positive Data Differential Output to line.
The exact function of this output pin depends upon whether the
XRT4500 is operating in the DCE or DTE Modes.
DTE Mode: Transmit Data (TXD) – Positive Polarity Output
Line Signal
Transmitter 1 accepts a TTL Level binary data stream (as the
“Transmit Data” – TXD) from the DTE Terminal Equipment.
Transmitter 1 converts this digital data into any of the following
electrical formats: V.10, V.11, V.28 and V.35, prior to transmis-
sion to the line.
If this data is being converted into either the V.11 or V.35 format,
then this pin outputs the positive-polarity portion of the “TXD”
data to the line. If this data is being converted into either the V.10
or V.28 formats, then this pin is inactive.
DCE Mode: Receive Data (RXD) – Positive Polarity Output
Line Signal
Transmitter 1 accepts a CMOS (or TTL) level signal binary data
stream (as the “Receive Data” – RXD) from the DCE Terminal
Equipment. Transmitter 1 converts this digital data into any of the
following electrical formats: V.10, V.11, V.28 and V.35 prior to
transmission to the line.
If this data is being converted into either the V.11 or V.35 format,
then this pin outputs the positive polarity portion of the “RXD”
data to the line. If this data is being converted into either the V.10
or V.28 formats, then this pin is inactive.
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