M4720 Monitors Ports&Responds to Custom Protocol

Featured Product from Electro Standards Laboratories

Model 4720 Single Channel DB25 A/B Switch, Monitor A & B for Control, Custom Protocol


  • PORT CONNECTORS: (3)  DB25 female connectors labeled A, B, and COMMON.
  • FRONT PANEL CONTROL: (1) Manual pushbutton allows local switching.
  • DISPLAY: (2) Red LED's display switch position, and power status.
  • POWER: UL approved, wall mount, 100VAC/240VAC, 50Hz/60Hz wall mount power module supplies 12VDC, 500mA to the unit. Has 2-prong, US, non-polarized plug.
  • DIMENSIONS: 7.5" W x 7.25" D x 2.0" H (19.1 x 18.4 x 5.1 cm).
  • WEIGHT: Approximately 2.5 lbs. 1.13 Kg

DB25 APPLICATION: The drawing illustrates a single channel of DB25 switching. A COMMON device connected to the DB25 COMMON port has access two other devices connected to the DB25 Port A (PRIMARY LINE), and the DB25 Port B (BACKUP LINE). The switch monitors data on ports A (PRIMARY LINE) and B (BACKUP LINE) and responds to custom protocol ASCII character.


  • Model 4720 allows quick connection to any one of two DB25 interface devices from one COMMON device.
  • Switches pins 1 - 8 and 20 of the DB25 interface. 
  • Local control via front panel pushbutton.
  • Data on both ports A and B looked to for ASCII character command sequences —  "Switch to A" commands received and responded to on port A; " Switch to B" commands received and responded to on port B.
  • ASCII commands are identified, stripped from data stream, and not allowed to pass through the A/B Switch unit.
  • Each received command is responded to for positive receipt of command acknowledgement.
  • Custom command protocol designed to enable the A/B Switch unit to respond per command acknowledge receipt of command and provide status information per command request.
  • RS232 multi-drop configuration for monitored data on ports A and B.
  • Each Switch has a programmable dip switch to create its unique address/identity.
  • Commands include CHANGE switch position, QUERY switch position status, and LOCKOUT/UNLOCK front panel control.
  • Front panel LED's display switch position and power status.
  • Retains last switch position in the event of power loss and continues to pass data.
  • Attractive anodized black box packaging provides EMI/RFI shielding.
  • Custom length DB25 cables available for your switch installation. 

The PathWay® Model 4720 Remotely Controllable DB25 A/B Switch monitors the data on its A and B ports and responds to custom protocol ASCII character "Switch to A" or "Switch to B" command sequences.  Local control is also available via front panel pushbutton.

Option: Wide Range Power Supply: (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.

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