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06/10/2021 - Technical Bulletin - VMAX IP Plus DW-VP9xT4P (3rd Generation) Alarm Input Ground                                                                         DW Technical Bulletin

To:  DW® Customers

Date:  June 10, 2021

Re:  VMAX® IP Plus™ DW-VP9xT4P Alarm Input Ground

VMAX® IP Plus™ DW-VP9xT4P (3rd Generation) Alarm Input Ground

Affected Model Numbers:  DW-VP9-4P

Effective Date:  June 10, 2021

When connecting alarm inputs of external sensors for alarms and event triggers to the 9-channel VMAX® IP Plus™ (DW-VP9xT4P), users will need to use the grounding screw of the NVR’s case to ground the RS-485 wire connections.

Identifying VMAX® IP Plus™ Model Generation

While the 1st and 2nd generation VMAX® IP Plus™ units have a dedicated RS-485 port to ground connections, the alarm input (RS-485) ports of the 3rd generation VMAX® IP Plus™ differs. When attaching an RS-485 connection to the alarm input of a 3rd generation unit, the installer will need to connect the negative pole wire to the screw (see image) above to ground the connection.

You can identify the generation of a VMAX® IP Plus™ by referring to the table below:


S/N Starts With

Firmware Filename

1st gen

2nd gen

3rd gen

1st gen

2nd gen

3rd gen






DW-VP09 vx.x.x.x

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Rev: 06/21                             Copyright © DW. All rights reserved. Specifications and pricing subject to change without notice.