CTC Union ETU-01A, Installation And Operation Manual

Page: 14 / 144

Chapter 1. Introduction
8
November 2001
•
External (DTE) timing :
The
ETU-01A
has three data channel clocking modes:
•
Clock mode DTE1: The
ETU-01A
data channel accepts the
user transmit clock from the connected DTE (from the ETC
pin) and provides a receive clock (Transparent timing) to the
synchronous equipment connected to the data channel.
•
Clock mode DTE2: The ETU-01A data channel accepts the
user transmit clock (from ETC pin) and receive clock (from
ERC pin) provided by the DTE equipment connected to the
data channel. Note: The X.21 data channel cannot be
operated in this mode.
•
Clock mode DTE3: The
ETU-01A
data channel operates as
a DCE and accepts both the user transmit and receive clock
(All from ETC pin) provided by the DTE equipment
connected to the data channel.