Crocus Bridge Interface
  • Interface modules for the Crocus baseband modems offering Ethernet Bridge functionality
  • Modular Plug-in module for maximum Flexibility and efficient Stock Management
  • Fully IEEE 802.3 compliant
  • Automatic LAN table learning and ageing
  • For all stand-alone models and card version models
  • Transparent and Nx64 Kbps version available

The CROCUS family of baseband modems can be equipped with a large set of modular exchangeable interfaces, making it the high speed interconnection solution for an extremely wide set of applications. A bridge interface modules combines the LAN and WAN subsystem in one single equipment. It automatically learns the MAC addresses on the LAN it is connected to and forwards through the Crocus baseband connection only those frames destined for another LAN. The Bridge’s LAN table can store up to 10000 addresses and features an automatic updating and ageing mechanism. The interface modules are fully compliant with the IEEE 802.3 standard and offer a direct UTP connection for connecting the Local Network. The polarity of the received signal on these interfaces is automatically corrected if reversed, as in the case of a wiring error. The Crocus baseband modem with a Bridge Module offers the ideal solution for a low cost interconnection between physically dispersed parts of a LAN subnet. (e.g. different buildings in a plant, campus networks, etc..).

Typical application 1: Interconnecting LANs in different buildings

It is also the central solution for concentrating different subnets through high speed baseband connections. Indeed: the combination with Crocus Twin modems offers a LAN concentration of 30 remote networks in just one Cardnest ! A typical application is the professional high speed Internet access.

At the customer side one has to install a Crocus table top model with bridge interface. The customer’s network can either be a single PC (A), a small network (B) or a large network (C). In the latter case, the network is connected to the Crocus through the customer’s router. At the central site, the Crocus modems are also equipped with Bridge interface modules. An Ethernet swith concentrates the different modules and forwards the traffic to the Internet backbone.

The Bridge interface exists as a transparent module which uses all the available bandwidth on the communication link for the transmission of Ethernet packets. On the other hand, it is also available in a version with Nx64 Kbps possibilities, which integrates the bridging and the rate conversion functionality on one single interface board. It allows for the selection of the speed of the Ethernet interconnection at any multiple of 64Kbps.

Typical application 2: Professional high speed Internet access

Typical application: LAN to LAN interconnect through a DACCS backbone


LAN interface:

RJ45 Unshielded Twisted Pair (UTP)

Automatic TP polarity reversal

fully IEEE 802.3 compatible


  • LNK: indicates the good Link integrity on the UTP interface
  • TX: indicates the LAN is transmitting data
  • RX: indicates the LAN is receiving data
  • COL: indicates the occurrence of a collision on the LAN
  • ERR: indicates an overrun/underrun in the bridge functionality

LAN encapsulation:

  • HDLC (16 bit CRC)
  • LAN CRC (32 bit) stripping and reconstruction
  • Enhanced Tinygram compression on LAN data

Bridge characteristics:

  • 10.000 address LAN table
  • 256 frame buffering
  • Automatic LAN Learning
  • Automatic LAN Ageing
  • Ageing time-out: 5 min

Nx64 Kbps functionality (Nx64 Kbps model only)

Configuration of any muliple of 64 KBps, up to the line speed G.704 compatible framing for direct interfacing on central cross conect systems

Configurable Ethernet interconnection speeds

Transparent Bridge
Nx64 Kbps Bridge
Crocus HS 48,56,64,72,96,112,128,144 Kbps -
Crocus SDSL 384, 768, 1152 Kbps Nx64 Kbps (Max 1152 Kbps)
Crocus HDSL 2048 Kbps Nx64 Kbps (Max 2048 Kbps)

Hardware configuration


  • Crocus HDSL equipment: see Crocus HDSL Leaflet
  • Crocus SDSL equipment: see Crocus SDSL Leaflet
  • Crocus HS equipment: see Crocus HS Leaflet
  • 152.489 BRIDGE INTF.(N.64K) CR SDSL/HDS

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