MC145574AAER2 Freescale Semiconductor, MC145574AAER2 Datasheet - Page 19

• Manufacturer Part Number: MC145574AAER2
• Manufacturer: Freescale Semiconductor

Specifications of MC145574AAER2

• Number Of Line Interfaces: 1
• Control Interface: HDLC
• Lead Free Status / Rohs Status: Compliant

MOTOROLA
2.1
2.2
INTRODUCTION
The MC145574 ISDN S/T transceiver conforms to CCITT I.430, ETSI ETS 300012, and ANSI T1.605
specifications. It is a layer 1 transceiver designed for use at the ISDN S and T reference points. It
is designed for both point–to–point and multipoint operation. The S/T transceiver is designed for use
in either the network terminating (NT) mode or in the terminal endpoint (TE) applications. Two 64 kpbs
B channels and one 16 kbps D channel are transmitted in a full–duplex fashion across the interface.
Sections 2.2 through 2.6 contain suggested wiring configurations for use. These configurations are
deemed to be the most common but by no means the only wiring configurations. Section 16 specifies
the recommended circuitry for interfacing the MC145574 to the S/T bus. Note that when operating
in the TE mode, only one TE has the 100
Figures 2–1 through 2–4 illustrate where to connect the termination resistors for the described loop
configurations.
A description of the most commonly used loop configurations is as described below.
POINT-TO-POINT OPERATION
In the point–to–point mode of operation, one NT communicates with one TE. As such, 100
tion resistors must be connected across the transmit and receive paths of both the NT and TE transceiv-
ers. Figure 2–1 illustrates this wiring configuration.
When using the MC145574 in this configuration, the NT must be in adaptive timing. This is accom-
plished by holding the FIX pin low; i.e., connecting it to V SS . Refer to Section 6 for a more detailed
description of this pin function. CCITT I.430, ETSI ETS 300012, and ANSI T1.605 specify that the
S/T transceiver must be able to operate up to a distance of 1 km in the point–to–point mode. This
is the distance D1 as shown in Figure 2–1.
MC145574
NT
RxN
TxN
RxP
TxP
Freescale Semiconductor, Inc.
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TR
TR
Go to: www.freescale.com
Figure 2–1. Point–to–Point
MC145574
WIRING CONFIGURATIONS
termination resistors in the transmit and receive paths.
D1
TR
TR
>
RxP
RxN
TxP
TxN
MC145574
TE
termina-
2
2–1