Chapter 1 - Introduction HCD-E1
Installation & Operation Manual
1-6 Functional Description 01/01/01 08:07
Each HCD-E1 data port supports the following control lines:
• RTS - input from the locally connected data equipment
• CTS - the user can permanently set the CTS line in the active state, or
can make the CTS line follow the RTS line.
• DSR - the DSR line is always active when the HCD-E1 is powered,
except when a remote main link test loopback is activated.
• DCD - the DCD line is active when the HCD-E1 main link interface is
synchronized.
E1 Link Interface
Characteristics
The HCD-E1 sublink (E1) interface meets the requirements of ITU G.703,
G.704, G.706, and G.732. HCD-E1 supports framed and unframed E1 data
streams. For framed data streams, HCD-E1 also supports the CRC-4 option
specified in ITU G.704. CRC-4 use is user-selectable.
The E1 port has two line interfaces: a 120-Ω balanced line interface
terminated in an RJ-45 eight-pin female connector, and a 75-Ω unbalanced
interface terminated in two BNC female coaxial connectors. Line coding is
HDB3. The nominal balanced interface transmit level is ±3V, and the
unbalanced interface transmit level is ±2.37V. The maximum allowed line
attenuation is up to 10 dB.
To increase the E1 sublink range, it can be ordered with an integral LTU. In
this case, the maximum line attenuation is 36 dB, enabling range of up to
2 km, using typical cables.
Jitter performance complies with the requirements of ITU G.823.
HDSL Subsystem
Characteristics
The HCD-E1 HDSL subsystem uses dual duplex transmission over two
2-wire lines. The line code on the HDSL lines is 2B1Q at a rate of
584 kbaud (equivalent to a data transfer rate of 1168 kbps).
Using advanced equalization, adaptive filtering, and echo cancellation
techniques, HCD-E1 compensates for line impairments, bridged taps, and
mixed cables commonly encountered in the local distribution network.
Moreover, due to its high immunity to background noise, HCD-E1 enables
the transmission of multiple HDSL signals in the same physical cable without
requiring pair selection.
HCD-E1 can operate on unloaded AWG-22, AWG-24, and AWG-26
twisted-wire pairs, and other similar pairs. Up to two bridged taps, having a
length of up to 500m, are tolerated. HCD-E1 achieves typical ranges of
4.8 km (3.0 miles) on AWG-24 (0.5 mm) pairs, and up to 3.8 km (2.4 miles)
on AWG-26 (0.4 mm) pairs. When working with the HDSL repeater
(H-RPT), typical ranges are up to 9.2 km (5.7 miles) from central to remote
unit on AWG-24 (0.5 mm) pairs, and up to 7.2 km (4.5 miles) from central
to remote unit on AWG-26 (0.4 mm) pairs. The HDSL line interfaces are
terminated in an RJ-45 eight-pin female connector.