RAD RSD-1 4 Channel Programmable Sharing Device 

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RAD RSD-1 4 Channel Programmable Sharing Device 


  • The RSD-1 Digital Sharing Device enables up to 4 modems or terminals to share a master modem, a multiplexer or a computer port in a multipoint environment. RSD-1 is compatible with asynchronous or synchronous equipment at data rates up to 19.2 kbps.
  • Three clock modes are supported:
    - Internal
    - External from the main channel
    - External from subchannel 1.
  • A built-in buffer overcomes possible phase differences between the RSD-1 main channel transmit clock and the clocks of modems connected to the subchannels.
  • A DCE/DTE switch for main channel and each subchannel allows setting the channel's interface as DCE or DTE.
  • The main channel broadcasts to all subchannels in parallel. Subchannels contend to transmit to the main channel by activating RTS/DCD or by data transitions (strap-selectable). If the RTS/DCD is active or data transitions occur on a subchannel, its transmit data and control signals are connected to the main channel. When RTS/DCD drops or data transitions stop, the control circuitry is switched to monitor other subchannels. A subchannel is disconnected immediately after it drops RTS/DCD or transmits 15 idle bits.
  • A subchannel can be disabled by automatic circuitry if it stays active for longer than a preset time, blocking all other subchannels (streaming). The automatic disable resets itself as soon as the subchannel RTS/DCD drops, or 15 idle bits are transmitted (Data Contention). Individual subchannel indicators on the front panel indicate if a subchannel was disabled by automatic circuitry. Manual disabling of a subchannel is also enabled via individual subchannel switches.
  • RSD-1 is available as a desktop unit or as a rack-mount card for the RSD-MN-12 rack. The rack can carry up to 12 RSD-1 cards and is supplied with 64-pin connectors. One or two power transformers are installed inside the rack providing hot standby backup.


  • Operates with any combination of up to four DTEs or DCEs
  • Synchronous or asynchronous up to 19.2 kbps
  • RTS/DCD or data contention
  • Individual subchannel disable switch
  • DCE/DTE switch for main channel and each subchannel
  • Automatic disabling of streaming subchannel to avoid blocking of the unit
  • Internal or external clock
  • Cascadable
  • Standalone unit or card for the RSD-MN-12 rack
  • Easy to install and configure
  • 1U height for minimal rack space

Digital sharing device, standalone unit with internal power supply

Digital sharing device card for the RSD-MN-12 19" rack

19" rack for 12 plug-in cards (single power supply)

RSD-MN-12 rack and control card, with dual redundant power supplies

* Specify power supply
(default is 115/230 VAC selectable)
48 for -48 VDC operation
& Specify buffer on each subchannel
(default is with no buffers)
B for buffers

64-pin connector to five 25-pin connectors for V.24 interfaces





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For discount pricing on RAD Data Communications  
email us at sales@data-connect.com
or call 301-924-7400