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Comarra offers its Ethernet over DS3 Switch (Ethernet to DS3 Switch) packaged in a 19-inch rack-mountable chassis.

Comarra Ethernet over DS3 Switch (Ethernet over DS3 Switch) provides a four 100BaseT Ethernet and 100Base-FX optical ethernet interfaces on the user side which may be used to transport Ethernet traffic over a DS3 link. Both ethernet interfaces may be used simultaneously. The Switch provides a simple and cost effective method to convert and transport ethernet data over an DS3 link.

Ethernet to DS3 Switch - Data Sheet

Features and Highlights

  • Ethernet interface to DS3 45 Mbps converter
  • 4x100BaseT full duplex fast ethernet interface in accordance with IEEE802.3
  • 3x + 1x100Base-FX full duplex optical ethernet interface accordance with IEEE802.3
  • Framed and un-framed DS3 options available
  • Local and Remote access and monitoring with either RS232 or 10/100BaseT for remote management over TCP-IP network
  • Power Supply: - 48 V DC or 110 V AC power supply options available.
  • Ethernet frame size: 2016 bytes (max)
  • Supports Jumbo Frames
  • Accommodates up to 8192 frames with a maximum frame size of 2016 bytes
  • Prevents any data overflows, or loss of packets in the event of a data burst.

Why we are better:

Our Ethernet over DS3 equipment offers the following necessary features that similar equipment from the other manufacturers do not offer or support...

  • We offer the option of Framed DS3 as well as Un-Framed DS3 option. The framing option is user programmable and use may select the DS3 interfaces as Framed DS3 or  Un-Framed DS3.

Note: Enabling the Framing option becomes essential when you inter-connect and use the equipment over an Sonet / SDH network. If you connect an Un-Framed DS3 interface of the equipment to a Framed DS3 network interface, the network is likely to show an error on the DS3 interface.

  • Our equipment allows the user to connect to, configure and manage the
    equipment remotely over a TCP-IP network. Most of the equipment being offered by the competition does not offer this feature.

  • Our equipment supports efficient handling of data, even during data bursts. Our product design provides a very large buffer data storage capacity to allow for and handle any data bursts very efficiently.

  • Supports Jumbo Frames: Our equipment is equipped with a Committed Information Rate controller (CIR) which manages any data overflows through its 100MHz SDRAM controller which interfaces to a 32-bit wide 128 Mbit SDRAM.  The SDRAM is used to buffer the data from the Ethernet and WAN ports for transport. It can accommodate up to 8192 frames with a maximum frame size of 2016 bytes to prevent any data overflows, or loss of packets in the event of a data burst.

Flow control is a part of basic ethernet communication protocol and the TCP-IP flow control protocol ensures that an optimum flow control is maintained at all times.

Note # 1: It is essential that the two routers / servers be operating in the same IP domain (subnet), since the Ethernet Over DS3 converter simply interconnects two LANS over a DS3 link. The Ethernet Over DS3 converter does not do any routing function. It simply provides a bridge to inter-connect two LANs over a DS3 link.

Note: The equipment should always be installed and used in pairs - with each unit to be installed at either end of the DS3 link.


  • 100 BaseT Ethernet and 100Base-FX optical to DS3 conversion (Ethernet over DS3).

Indications and Alarm Monitoring

  • DS3 Loss of Signal
  • Loss of DS3 frame (in framed DS3 mode)
  • Loss of incoming signal at 100 BaseT Ethernet
  • Loss of ethernet packets, errored ethernet packets, over-sized ethernet packets and under-sized ethernet packets log.
  • Configuration Error Alarm
  • Clock Status
  • +3 Volts Power Supply
  • -48V DC present
  • Configuration Error

Programmable Features

  • Telnet interface for remote programming and monitoring by using CLI text commands
  • Easy to use programming using Windows based GUI.

Status Monitoring

  • Status of alarms on DS3 interface

  • Status of alarms on 100BaseT interface.

Ethernet Interface

Interface Types 100BaseT and 100Base-FX optical
Standards Compliance IEEE 802.3-2002
Interface Rate 100BaseT limited to DS3 transmission rate
Protocol HDLC/X.86 (LAPS) Encapsulation

DS3 Interface

Bit Rate 44.736 Mbps
Bit Rate Tolerance 20ppm
Line Code B3ZS
Framing options Meets ANSI T1.404
M13 (M23)
Pulse Shape Meets ANSI
T1.102-1993 and
Bellcore GR-499-CORE
Connectors BNC, Co-axial
Impedance 75 Ohms
Signal Level to declare Loss of Signal condition < 20mV
Signal Level to clear Loss of Signal condition > 90 mV

Application Diagram

Technical Specifications

DC Adapter Power Supply Specifications (DC Option)

Power Supply -48V DC (-40V DC to -60V DC)
Input DC voltage -48V DC ( nominal )
Range of input -40V to -60V DC
Output voltages +3.3V
Full Load Output Current 2A at +3.3V
Input Voltage Reversal Protection Provided in the Card
Over Current Protection 2A for +3.3V
Short Circuit Protection Current limit - 3A. Recovers on removal of short
Under Voltage < 3.17V
Over Voltage 3.5V
Efficiency at full load >90%
Ripple at full load <5mVrms
Spike at full load <50mV

AC Adapter Power Supply Specifications (AC Option)

Input AC voltage of AC Adapter 100 - 240 Volt AC
Range of input AC voltage 100 V to 240 V AC
System Input voltage 7.5 V DC to 9.0 V DC, DC input polarity protection.
Maximum full load output Current 2.5 A at 7.5 V DC / 9.0 V DC
Input voltage reversal Protection Provided in the Card
Efficiency at full load >86%


  • 1U High
  • 19-inch rack-mounting shelf.

Power Supply

Power Supply -48V DC (-40V DC to -60V DC) (Optional)*
Power Supply AC input (Optional)*
* Please specify the Power Supply Option (AC or DC) which is required before placing the order. Please see ordering information in this data sheet for details.

Power Consumption

Power Consumption: 9 Watts

Number of Ethernet Interface

10/100BaseT (Electrical) 4
10/100BaseT Electrical + 100Base FX Optical 3 Electrical and 1 Optical

100BaseT Interface (Electrical Ethernet)

Interface Types 100BaseT
Standards Compliance IEEE 802.3-2002, RFC1662, RFC2615, X.86, RMII
Interface Rate 100BaseT limited to DS3 transmission rate
Protocol HDLC/X.86 (LAPS) Encapsulation
Connectors RJ-45 (100 BaseT Electrical)

100BaseT-FX Interface (Optical Ethernet)

Interface Types 100BaseT-FX
Standards Compliance IEEE 802.3-2002, RFC1662, RFC2615, X.86, RMII
Interface Rate 100BaseT-FX optical limited to DS3 transmission rate
Protocol HDLC/X.86 (LAPS) Encapsulation
Connectors SC


Internal System Internal Clock
Loop-Timed Timed from DS3 Interface

Management and Control

  • Serial Management Port - RS232 Interface
  • 10/100 BaseT for Remote Management over a LAN
  • 10/100 BaseT Telnet over a TCP-IP Network

Command Language

  • Command Line Interface (English text commands)
  • Windows based GUI (optional)

NMS (with Telnet) XPort Specifications

Network interface RJ-45 Ethernet 10BaseT or 100BaseT-TX (auto sensing)
Compatibility Ethernet Version 2.0 IEEE802.3
Protocols supported ARP, UDP/IP, TCP/IP, Telnet, ICMP, SNMP, DHCP,  BOOTP, TFTP, Auto IP, SMTP and HTTP
LEDs 10Base-T and 100Base-TX Activity, Full/half duplex
Management Internal web server, SNMP (read only), Serial login, Telnet login
EMI compliance


  • Radiated and conducted emissions - complies with Class B limits of EN55022:1998
  • Direct and Indirect ESD - complies with EN55024:1998
  • RF Electromagnetic Field Immunity - complies with EN55024:1998
  • Electrical Fast Transient/Burst Immunity - complies with EN55024:1998
  • Power Frequency Magnetic Field Immunity - complies with EN55024:1998
  • RF Common Mode Conducted Susceptibility - complies with EN55024:1998

Others Links:

  STM SDH Multiplexers
  E1 VoIP-GSM Gateways
  VoIP SS7 and C7 Solution
  Echo Cancellers and VQE Solutions
  GSM Gateways / GSM Channel Banks
  E1 and T1 over Ethernet (TDM over IP)
  Digital Access Cross Connect Switch (DACS)
  E1, T1, E3, DS3, Ethernet Converter (IP over TDM)

Technical specifications are subject to change without notice.
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