WC X.21: Ethernet over X.21 Extender

WC X.21: Ethernet over X.21 Extender

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WC X.21 LAN extender product offers a simple "plug and play" method to extend a LAN connection between multiple sites using an X.21 leased line.

The integrated 4-port LAN switch supports local switching, thereby removing the need for external switches or hubs in smaller LAN installations.

Front: WCX21Front: WCX21

LAN Extension over Serial X.21 leased lines

Please Note:

The WC X.21 product has now been superceded by the more flexible MetroCONNECT: WC-Serial or the fully manageable MetroCONNECT WCM-Serial product which offers advanced functionality at a cost-effective price point. The WC X.21 is no longer available.

WAN-in-a-Can Overview Diagram

WAN-in-a-Can : the "plug and play" way to connect LANs together over the WAN

  • Must be used in pairs
  • Feature rich LAN extender over X.21 leased lines
  • Quad port Ethernet switch on subscriber side, with wirespeed local switching
  • 4 Auto-negotiating subscriber 10/100 BaseT ports, with auto MDI/MDIX switching
  • Wire speed filtering of local packets
  • Efficient HDLC encapsulation on WAN port
  • Easy to install & maintain
  • Integral auto-sensing power supply (100-250V AC or -40V DC versions)
  • 12-24V DC power supply available on request
  • Compact modem style unit, built to European standards
  • Rack mounting kits for 2 or 18 units available
  • Can also be used to offer asymmetric Ethernet services via EIA530 satellite modems
  • Higher specification MetroCONNECT managed LAN extenders are also available
Related Products Applications

Connecting two LANs together using an X.21 leased line

LAN Extension over X.21

This application shows two LANs connected together using an X.21 leased line, such as a BT Kilostream-N circuit. As a plug and play Ethernet switching device the WC X.21 is a straight forward and cost effective alternative to the use of routers in small and medium sized networks.

Connecting two LANs together using a fractional E1 Nx64kbps G.703 leased line

LAN extension over Fractional E1 Nx64kbps leased line

This application shows two LANs connected together using a fractional E1 Nx64kbps G.703 leased line, such as a BT Kilostream-N circuit with G.703 connectivity. In this case the WC X.21 is used in conjunction with a DC3000 to interface to the leased line. As plug and play Ethernet switching devices the WC X.21 is a straight forward and cost effective alternative to the use of routers in small and medium sized networks.

Delivering an asymmetric Ethernet service via an EIA530 satellite modem

LAN over EIA530 satellite link

This application shows an Ethernet service delivered via an EIA530 satellite modem. In this application the WC X.21 supports local switching, wirespeed filtering and asymmetric data rates up to 20Mbps with an absolute minimum of overhead. This application requires another WC X.21 unit at the other end of the satellite link, and the use of a proprietary EIA530 to X.21 conversion cable.

Full wirespeed switching and filtering between the 10/100 BaseT LAN ports is supported so that only packets destined for the remote site are forwarded over the Nx64kbps leased line.

In most installations the WC X.21 requires no configuration, and is therefore truly "plug and play". The subscriber ports perform auto-negotiation and support both 10M and 100M operation in full duplex (FD) or half duplex (HD) modes. Manual selection of 100M FD operation enables connection to fixed router ports. Cabling issues are minimised through the use of automatic MDI/MDIX selection on these ports.

The highly efficient HDLC encapsulation of packets ensures that maximum throughput is achieved on the WAN link. Internal packet buffering enables each WC X.21 to smooth out bursty traffic without packet loss.

The serial port operates in DTE mode, and requires the attached DCE (e.g. Kilostream NTU) to supply timing.

The WC X.21 can also be operated in a dual-clock EIA530 mode to support asymmetric operation with an EIA530 satellite modem . An external cable can be used to convert the X.21 interface into EIA530 for connection to the satellite modem.

The WC X.21 supports a maximum packet size (MTU) of 1536 bytes which is sufficient to transport double VLAN tagged frames (Q-in-Q).

The WC X.21 units can easily be rackmounted in either a 1U two unit rackmount kit, in a 6U eighteen unit rackmount kit or are available in a 1U quad box (1U rackmountable unit containing 4 x WC X.21 units).

Subscriber Port
No. of Ports 4
Presentation 10/100 Base TX, RJ45, Auto-MDI/MDI-X
LED Support Link / Activity & Speed
Operating Mode Auto-negotiate for 10/100, Full or Half Duplex
Port Filtering Rate 148810 packets/second
Port Switching Rate 148810 packets/second
Switch Mode Any to any
MAC Address Table 4096 entires
Packet Size 64 bytes minimum
1536 bytes maximum (older versions support 1522 bytes maximum for auto negotiation mode and 1536 bytes for fixed 100M FD mode)
WAN Port Specs
WC X.21
Mode Serial
Presentation15 way Male D Type
Line Rate 20Mbps (max)
Frame Mode Unframed
Timing DCE Supplied
Encapsulation HDLC
Max Packet Rate 38462 at 20Mbps
LEDs Tx/Rx Packet
Alarms None
Diagnostics None
Type Modem, 1U high without feet, IP30C
Dimensions W x D x H mm
Rackmount 202 x 132 x 44 (without feet)
Desktop 202 x 132 x 48 (with feet)
Temp 0 - 50 deg C
Humidity 95% RH, non-condensing
Pressure 86 - 106 KPA
Power Supply
AC Mains 100-250VAC, 50-60Hz, 60-24mA IEC Connector
-48VDC -40 to -72VDC, 200-100mA
Order Code
AC Mains: 100 - 250 VAC DC Power: -48 VDC
WC X.2180-05-54580-21-545
2 Unit Rackmount Kit80-05-25680-05-256
18 Unit Rackmount Kit80-05-25080-05-255
Quad WC X.2180-405-54580-421-545

Product variants with 12V to 24V DC operation are also available on request.

MetroCONNECT Ethernet Service Delivery Products - Standalone Units
MetroCONNECT Ethernet Service Delivery Products - Chassis System
Ethernet Extenders

Networking The World Since 1989