DB25 Automatic Fallback Switch with Telnet Remote

Featured Product from Electro Standards Laboratories

Path Way® Remotely Controllable Network Switch, DB25
Model 4209 DB25 Automatic Fallback Switch with Telnet Remote 

  = Automatic Fallback Mode or Manual Mode


  • PORT CONNECTORS: (3) DB25 female connectors labeled A, B, and COMMON. 
  • FRONT PANEL CONTROL: (3) Manual pushbuttons; (1) Positional, (1) Manual Mode, and (1) Automatic Fallback Mode). 
  • DISPLAY: (4) LED's;  (2) Positional Green LED's, (1) Blue LED (Auto Fallback Mode), (1) Blue LED (Manual Mode)
  • REMOTE CONTROL: (1) RJ45 female connector on rear panel accepts 10/100 Base-T LAN Access Ethernet that uses TELNET commands for Remote Control operation.
  • POWER: UL approved 100VAC/240VAC 50 Hz/60Hz wall mount power module supplies 12VDC, 500 mA to the unit.
  • DIMENSIONS: Desktop configuration 8.11" W x 2.42" H x 7.30" D (20.6 x 6.2 x 18.6 cm) 
  • WEIGHT:  Approximately 2.0 lbs. (0.9 kg)

PathWay® Model 4209 DB25 Automatic Fallback Switch with Telnet Remote: 
The drawing illustrates a COMMON Device connected to the DB25 COMMON port with access to a Primary Line connected to Port A and a Secondary Line connected to Port B. The unit monitors Port B for data activity. The Remote RJ45 10/100Base-T LAN Ethernet port can be used to remotely control the unit via Telnet Commands and is IP Addressable!   

  • Activity on Port B = B position; 
  • No activity on Port B = A position
  • Auto Sense to automatically change position based on presence or absence of signal on Port B.

PathWay® Model 4209 Automatic Fallback DB25 Switch with Telnet Remote Application drawing.


  • The switch ports are transparent to data.
  • All (25) pins of the DB25 interface are switched via break-before-make electromechanical relays.
  • Pins 4 and 19 of the B port are monitored for RTS being active.
  • The unit maintains last set position on power loss and continues to pass data.
  • Front panel pushbutton control.
  • Automatic fallback mode and manual mode.
  • Control of the switch position from a 10/100Base-T LAN Ethernet environment.
  • Remote Control Telnet command interface that allows the user to control switch position, lockout front panel operations, toggle between automatic and manual modes, obtain switch status, as well as, query firmware version number, query serial number and enable/disable autosend of switch positions.
  • Front panel LED's display the present position and power status.
  • The unit automatically switches to the B position, when data is detected on port B.
  • Unit chassis ground is connected to the signal ground.
  • Attractive all metal black box packaging provides EMI/RFI shielding.
  • Custom length DB25 cables available for your switch installation. 

The PathWay® Model 4209 DB25 A/B Automatic Fallback Switch with Telnet Remote allows the user the capability of sharing a single DB25 interface device connected to the Common port among two other devices connected to the A and B ports. The Model 4209 is packaged in a slim desktop style enclosure.

The switch may be controlled manually via front panel pushbutton, or Remote Control. Remote access can be accomplished using an Ethernet 10/100Base-T connection and Telnet commands.  The front panel LED display indicates the switch position, and power status. 

The unit monitors data activity on port "B". If the unit is in the A position and data activity is present on port B, the unit automatically switches to the B position. The unit will then remain in the B position until signal is not present, in which the unit will switch back to the A position automatically. 

Wide Range Power Option Available: (Cat No. 517277) CE, RoHS, and UL listed table mount power module, 100VAC/240VAC, 50/60Hz for use in place of the standard power module that is included with the unit.  Has IEC 60320 C14 inlet. Ideal for international applications.

 For custom network switches call our friendly customer support staff at 401-943-1164 or email eslab@electrostandards.com.

All ESL products are available for export.