RAD HCD-E1 HDSL E1 Access Unit

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RAD HCD-E1 HDSL E1 Access Unit 

  • HCD-E1 is an access unit that converts n x 56, n x 64 kbps or fractional or full E1 signals into HDSL transmission format. The conversion extends the transmission range to cover 4.8 km (3.0 miles) over a 4-wire link, or 2.5 km (1.6 miles) over a 2-wire link (24 AWG / 0.5 mm) without the need for repeaters or fiber optic link.
  • HCD-E1 can be ordered with one or two different data ports, and with a sub-E1 drop & insert port. The data port rates are selectable for any multiple of 56 or 64 kbps. The user data of each port is placed into an E1 frame, using specified timeslots, and then converted into an HDSL frame. Each timeslot of the sub-E1 port is placed in the same timeslot as the HDSL E1 frame.
  • Transmission of HCD-E1 complies with the ETSI HDSL standards. The unit compensates for line impairment, bridge taps and mixed cabling by using equalization technology, adaptive filtering, echo cancelling and 2B1Q line coding. These factors provide high immunity to background noise and enable the transmission of multiple HDSL lines over the same physical cable.
  • An embedded channel in the HDSL transmission provides both control and diagnostic capabilities from a central HDSL device, up to the remote unit at the customer's premises. The user can monitor the link and alarms, and perform online configuration, as well as diagnostic loops to the remote unit.
  • HCD-E1 can operate opposite other RAD HDSL products, such as HTU-E1, HTU-2 and H-RPT. This enables one type of HDSL equipment to manage another type at a remote location.
  • Two data ports are available with the following interfaces: RS-530, V.35, X.21 and RS-449/V.36. Another ordering option is a built in Ethernet (10BaseT) bridge, which enables a LAN-to-LAN connectivity using the HDSL technology. When ordering the Ethernet bridge option, one of the data ports is the Ethernet connection and the other data port can be one of the following four types of interfaces: RS-530, V.35, X.21 or RS-449/V.36.
  • Timeslot assignment is programmable, allowing data from each data port and from the sub E1 port to be placed into timeslots, either consecutively or alternately. HCD-E1 provides full user control of the data ports timeslot allocation without restrictions.
  • Multiple clock source selection ensures maximum flexibility for supporting different applications. The main HDSL link may be clocked from the recovered receive clock, from an internal oscillator, from one of the data ports or from the sub-E1 port. The data channels may be set to the following clock options:
    • DCE - where the data channel provides both transmit and receive clocks to the user DTE
    • DTE1 - where the data channel provides the receive clock to the user while receiving the transmit clock from the user DTE
    • DTE2 - where the data channel receives both the transmit and receive clocks from the user DCE.
  • The sub-E1 interface complies with ITU recommendations G.703 and G.704 and can work with or without CRC-4. HDB-3 zero suppression is used.
  • The priority bumping feature allows the user to select the timeslot priority (high or low) in case one of the HDSL lines is down.
  • Setup, control and monitoring of status and diagnostics information can be performed using one of the following:
    • Front panel LCD with three push buttons, using menu driven management
    • ASCII terminal connected to the async control port using command line interpreter
    • SNMP management station connected to the async control port, using Serial Link Interface Protocol (SLIP).
  • HCD-E1 can be managed via a dedicated E1 or HDSL timeslot.
  • HCD-E1 supports an internal SNMP agent and can be controlled by any generic SNMP station or by the RADview SNMP network management application.
  • When working opposite an HDSL card in the LRS-12 rack, a direct Ethernet connection is available for central SNMP management.
  • HCD-E1 is available as a standalone unit for desktop use or for installation in a 19" rack. A rack-mount adapter kit enables installation of one or two standalone units side by side.


  • Converts n x 64, n x 56 or full E1 data rates to HDSL transmission format
  • Range of up to 9.2 km (5.7 miles) with H-RPT repeater or up to 4.8 km (3 miles) without repeater
  • Operates opposite RAD's HTU-E1, HTU-2 and H-RPT
  • Complies with the ETSI HDSL standards
  • Two data ports with the following interfaces: V.35, RS-530, RS-449/442, X.21, or built-in Ethernet bridge
  • Optional sub-E1 drop & insert port for PABX connectivity
  • Built-in SNMP agent for standalone and card versions
  • Setup, control and monitoring via front panel or ASCII terminal
  • Sub-E1 interface complies with ITU G.703, G.704, G.706, G.723 and G.823
  • Supports priority bumping
  • 100 alarm records
  • Alarm relay activation upon alarm event
  • 24 hour storage of network performance monitoring
  • Enhanced diagnostics include:
    • User-activated local and remote loopbacks
    • Integrated BER tester
    • Fractional E1 in-band loop
  • High voltage line protection in compliance with ITU K.21

HDSL E1 Access unit, standalone, with HDSL over 4-wire line

HDSL E1 Access unit, standalone, with HDSL over 2-wire line

* Specify supply voltage
AC for 115 or 230 VAC
48 for -48 VDC
+ Specify sub-E1 option
(default is without sub-E1)
S1 for sub-E1 interface
$ Specify number of ports
1 for one data port
2 for two data ports
& Specify digital interface
V35 for V.35 interface
X21 for X.21 interface
530 for RS-530 interface
V36 for RS-449/V.36 interface
UTP for 10BaseT and one data port
BNC for 10Base2 and one data port





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