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*Automatic Channel Sequencing* Model 4441, 4-Channel DB9 RS232 Port Sharer, Catalog #304441

    DB9 RS232 Data Port SharerDB9 RS232 Data Port SharerDB9 RS232 Data Port SharerDB9 RS232 Data Port Sharer
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    • DB9 RS232 Data Port Sharer
    • DB9 RS232 Data Port Sharer
    • DB9 RS232 Data Port Sharer
    • DB9 RS232 Data Port Sharer
Base Price:
Catalog No: 304441
Model No: 4441
Product Type:Switches: Copper
Cable Type/Port Connector:DB9 Switch Ports
Electronic Switches/Power Required:PathWay® Copper
Pins Switched:3 (TD, RD and SG)
Comments:Allows 4 data Channels to Contend for One Port


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  • To return an item, contact Electro Standards at 401-943-1164 to obtain a Return Material Authorization (RMA) number. RMA numbers are valid for 30 days after the date of the shipment and cannot be extended or re-issued. We are unable to accept returns without an RMA number.
  • All returns except those of defective product are subject to a 15% restocking fee, and additional charges for handling or freight are refunded only in cases of defective products.
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  • If your item is not working properly, please contact Electro Standards at 401-943-1164 for help in trouble-shooting your application.
  • If the product is defective, Electro Standards will repair or replace that item (at our discretion) upon receipt and evaluation of the original product.
  • Electro Standards reserves the right to authorize product returns after 30 days from the invoice date in some cases. If the product is accepted after 30 days, credit will be issued toward future pruchases only and some additional restocking charges may be applied.
  • All credits from RMAs must be used within one calendar year of issue.

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Path Way® RS232 Serial Data Port Sharer
Model 4441 4-Channel DB9 RS232 Serial Data Port Sharer with Data Activity Enabled Port Contention

  • Automatic "Channel Sequencing" allows 4 data channels to access one port!

  • Automatic Port Contention expands accessibility of four channels to host computer.


  • PORT AND CHANNEL CONNECTORS: (5) DB9 Female connectors labeled A, B, C, D and Common.
  • FRONT PANEL CONTROL: (1) Manual pushbutton allows local channel selection control.
  • DISPLAY: (5) Front panel LED's display sharer scanning and power status.
  • POWER: UL Approved 120VAC, 60Hz wall mount power module supplies12 VDC to the unit.
  • DIMENSIONS: Desktop, 8.0" W x 8.0" D x 2.5" H. (20.3 x 20.3 x 6.4 cm)
  • WEIGHT: Approximately 3.5 lbs (1.6 kg)


  • "Automatic "Channel Sequencing"
  • "Automatic Port Contention"

The diagram illustrates four asynchronous data channels A, B, C, and D to contend for access to one Host Computer connected to the DB9 COMMON port. Channels A, B, C, and D are sequentially scanned and monitored based on data activity. (Automatic Channel Sequencing Circuitry) 

PathWay® Model 4441 4-Channel DB9 RS232 Port Sharer, Data Activity Port Contention, Model 4441 App Note


  • A "CONTENTION-TYPE" port sharer.
  • Allows four asynchronous data channels, A/B/C/D, to contend for access to one Common port.
  • Front panel LED's display channel scanning status and power status.
  • Signals supported: TD, RD, and SG.
  • Selectable timeout period.
  • Front panel control allows disabling of any erroneous streaming data channel.
  • For a "BROADCAST-TYPE", see Model 8982, Cat.No.302077.

The PathWay® Model 4441 is a four channel, port sharing device.  It allows a single destination port, the Common port, to automatically connect through to any of four source channels, A, B, C, or D based on data activity.

Each of these respective four DB9 RS232 serial interface source channels contend for connection.  Channels A, B, C, or D are sequentially scanned or monitored for data activity.  Once data is detected on a single channel, the remaining three channels are locked out until the data traffic stops and is absent for a preset timeout period.  At that point, the Model 4441 4-channel data sharer resumes monitoring of all four channels for data activity.  There are status LED's that indicate the unit is scanning, or whether the unit has established a dedicated connection to a single channel.


The devices connected to channels A, B, C and D of the Model 4441 sharing unit contend for connection to the Common port device.  Once activity is initiated on a source port A, B, C, or D, that channel is serviced.  Connection is maintained while data activity is detected between pin 3, TD, of the DB9 source channel and pin 2, RD, of the DB9 destination / Common port.  The signals supported by the Model 4441 are TD, RD, and SG.

While connected and data activity is present, the scanning is suspended.  The channel is released, and scanning is resumed only after data activity has been absent for a programmed timeout period, or if the channel is disabled via the front panel pushbutton switch.

The timeout period is selectable via a dipswitch located on the top circuit board inside the unit.  The program switch is accessible by removing the four screws that fasten the top cover to unit.  The Model 4441 is factory set for a one-minute timeout period.  To change the period, please refer to the Operation Manual.

If a connected device is streaming erroneous data, the user can use the front panel pushbutton switch to disable the channel and remove it from the scanning/monitoring function.   Disabling the channel will allow the unit to continue to function as a port sharer among the remaining channels and connected devices.

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