Crocus SDSL Quad

  • Stackable access multiplexer with integrated SDSL technology
  • Configurable access speeds per user between 64 kbps and 1152 kbps
  • 4 SDSL modems per card
  • Channelised E1 up-link for connectivity to backbone equipment
  • Stackable through G.703 drop and insert interface
  • Compatible with remote Crocus SDSL desktop equipment
  • High-density solution offering up to 60 modems per card-nest
  • Cost reduction of 50% in the access connectivity

XDSL connectivity combined with access multiplexing

The Crocus SDSL quad combines high-speed xDSL connectivity with access concentration on a channelised E1 interface. It is ideally suited to environments where a concentration of remote users is required whilst minimising the number of interfaces towards the backbone equipment. The reduced number of interfaces on the backbone device drastically limits the cost and the dimensions of this backbone equipment.

Each Crocus SDSL quad card accommodates 4 SDSL modems, terminating 4 different users connected through a regular twisted copper pair. Each modem can be configured for operation at any multiple of 64 kbps (up to 1152 kbps). The data-traffic from the different users is aggregated onto a G.703 interface with E1 framing. Allocation of the time-slots on the G.703/E1 interface is completely controlled by the operator.

Should more than 4 users have to be accommodated on a single G.703/E1 interface, different Crocus SDSL quad cards can be cascaded in order to further increase the user density per interface. In total 31 time-slots of 64 kbps can be divided between the different connected users. This typical topology is shown in the following figure.

Global cost reduction

The figure below shows the global cost of a high-end Frame-Relay access node (Switch and SDSL access equipment). Both the solution with classical interfacing to the switch through V.35 interfaces, and the solution with channelised E1 interfacing are shown (the graphs are given for average access speeds of 256 kbps and 64 kbps per user). The cost reduction is mainly acquired thanks to substantial savings on the number of physical ports on the backbone equipment. Similar cost saving can be achieved when interfacing to router backbone equipment (in network topologies as they are commonly implemented for Internet Service Provisioning).


The Crocus SDSL quad cards are accommodated in either a desktop housing (4 cards) or a high density 19" card-nest (15 cards), which allows a concentration of up to 60 users. These housings can combine the Crocus SDSL quad with other equipment (e.g. Crocus HDSL, Crocus FO10M..), offering a global access solution. Both types are designed to provide full power redundancy and allow for powering at 48Vdc or 230/115 Vac.


The Crocus SDSL quad can be managed together with other Telindus access equipment in an integrated way by using a high-performance integrated SNMP-based management system (HP Openview). An embedded auxiliary channel on the communication link transmits the management information to remote modems rapidly and efficiently.

In order to optimise the service on the installed network Telindus also offers a free Windows based maintenance package. This is a valuable tool for the field engineer as it supports full configuration and troubleshooting facilities for both the local and remote equipment.


The Crocus SDSL quad can be equipped with two exchangeable interfaces, and offers following combinations.

In this most basic configuration, the Crocus SDSL Quad multiplexes up to four remote users on a single channelised E1 backbone interface.

Cascaded Crocus SDSL Quad modems allow to increase the number of users connected to the channelised E1 backbone interface.

Two separate channelised E1 backbone interfaces allow to concentrate high-speed users when the total bandwidth of the users exceeds the capacity of one E1 interface.

In addition to the remote users an Nx64k interface allows a local user to be connected simultaneously. This user can be connected at any multiple of 64 kbps, and can use X.21, V.35, V.36, RS-530, V.24 or Ethernet 10Base-T interfaces.


Line interface

Single pair line access per modem
Number of modems per card: 4
Connector: screws
Impedance: 135 ohm
Coding: 2B1Q (HDSL based)
Modulation speeds: 128, 384, 768, 1152, kbps

Configurable user speeds

Line speed     Configurable user speed

128 kbps            Nx64 kbps (N=1..2)
384 kbps            Nx64 kbps (N=1..6)
768 kbps            Nx64 kbps (N=1..12)
1152 kbps          Nx64 kbps (N=1..18)

The mapping of the user connections on time-slots of the G.703/E1 interface is entirely under operator control.

Primary backbone interface

Field exchangeable

    User speed: E1 2 Mbps
    Connector:   RJ45 (120 ohm)
                        BNC (75 ohm)

Secondary cascade interfaces

Field exchangeable

    User speed: Fractional E1 (cascade)
    Connector:   RJ45 (120 ohm)
                        BNC (75 ohm)
    User speed: Nx64 kbps (N=1..31)
    Connector: ISO 2593 (female 1,6mm pin)
    User speed: Nx64 kbps (N=1..31)
    Connector: ISO 4902 (DB37 female)
    User speed: Nx64 kbps (N=1..31)
    Connector: ISO 4903 (DB15 female)
    User speed: Nx64 kbps (N=1..31)
    Connector: ISO 2110 (DB25 female)
Ethernet Bridge
    Connector: 10Base-T (RJ45)
    User speed: Nx64 kbps (N=1..31)

Management interface

Synchronous High speed bus (RJ45)
9600 bps asynchronous (subD 9-pin)

Front panel

General indications
    PWR: Power
    AIS Upper : AIS/LFA/LOS indication for primary backbone interface
    AIS Lower: AIS/LFA/LOS indication for G.703 cascade interface (if present)

Indications per modem
    ERR : Error Test error indication/Local alarm indication
    109/DCD : Signal Quality indication and Data Carrier Detect (circuit 109)
    TST: Test Indicator

Test loops per modem
    AL: Analogue Loop
    RDL: Remote Digital Loop
    DL: local Digital Loop
    ET: Integrated Error test generator (Test pattern 215-1)

Supplementary features

The card has a flash memory to allow firmware upgrades.
Maintenance of local card and remote modems with free Windows software
Integrated network management module for HP OpenView

Mechanical data

Rack-mount card (4 modems) H x W x D: 235 x 20 x 300 mm
        weight: 1 kg
Cardnest CN4 (15 card-positions) H x W x D: 6U x 19" x 350 mm
Desktop CN4 (4 card-positions) H x W x D: 6U x 170 mm x 350 mm

Environmental Requirements

Ambient operational temperature 0C to 50
Storage temperature -25C to +70C
Maximum altitude 3000 m
Relative humidity 0% to 95% non-condensing

Power Requirements (per card)

48Vdc (36Vdc - 72Vdc) : 190 mA

Crocus SDSL Quad sales items

Basic Crocus SDSL Quad card


G.703 primary backbone interface


Secondary cascade interfaces

149.378 V35 (N.64K) INTF.CROCUS
149.377 V36 (N.64K) INTF.CROCUS
149.379 X21 (N.64K) INTF.CROCUS
161.612 RS-530 (NX64K) INTF.CROCUS

Power module (not needed with 48Vdc powering)

142.190 PWR MOD 220/110V CN4 80W (for 4-slots housing)
143.678 PWR MOD 220/110V CN4 300W (for 15-slots housing)

Housing items

142.189 CARDNEST CN4 (15 slots)
163.459 DESKTOP CN4 (4 slots)

Controller card (for optional IP based management)

153148 O1003LAN CV-CN4

Single card-unit (4 modems)

Note: Telindus may make improvements and/or changes in the products described above at any time, without notice and shall in no way be held responsible for errors in this document.

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