PairGain ETU-772, Quick Installation Manual, Page: 7 / 32

700-722-900-02, Revision 02 Overview
UTU-722 and ETU-772 List 1 June 21, 1999 1
O
VERVIEW
This guide contains installation information for the PairGain
®
HiGain-ETSI™
UTU-722 List 1 and ETU-772 List 1 Rate Selectable (RS) line and desktop
units.
R
ATE
S
ELECTABLE
HDSL
HiGain-ETSI RS is a single pair High-bit-rate Digital Subscriber Line
(HDSL) solution that offers extended reach capabilities through the use of
industry-leading multi-rate DSL technology. The UTU-722 and ETU-772
deploy HDSL in networks using a single pair of copper wire running at speeds
between 64 kbps and 256 kbps. The HDSL line rates are either menu selected
in time slot increments of 64 kbps or derived automatically from the Terminal
Transmission (TT) clock received at the Nx64k serial data port from the
Network Data Terminal Equipment (DTE). Transmission ranges vary
according to the rate selected. Depending on noise environment, ranges of up
to 8.5 km (5.3 miles) are possible at the lowest-selectable HDSL line rates
(64 and 128 kbps).
UTU-722 L
INE
U
NIT
The UTU-722 can be configured as a Line Termination Unit (LTU) or
Network Termination Unit (NTU). The default configuration is NTU.
When configured as an LTU, the UTU-722 serves as the Exchange Office
side of a repeaterless, HDSL transmission system. The LTU-configured unit
connects to an NTU-configured unit (UTU-722 or ETU-772) over one
twisted-pair of copper wire, completing the HDSL transmission system.
The UTU-722 has an Nx64k serial data interface with user-selectable
protocols that include V.35, V.36, X.21, and RS-530 (RS-449). The
UTU-722 accepts the DTE payload at its Nx64k serial data port and
transports the data to the remote unit at the selected HDSL rate. The UTU-722
requires -36 to -72 Vdc from a local power supply or an enclosure’s
AC-to-DC power supply; it does not supply power to other HDSL units.
HiGain-ETSI RS units are not backward compatible with
standard HDSL or management unit firmware. The installed
firmware must be that designed for rate selectable units.
HiGain-ETSI RS units must have the same payload rates
available. An LTU set for a rate of 768 kbps will not function
with an NTU whose maximum available rate is 256 kbps.