The correct answer isOSN 1800 I. TheOSN 1800 Idoes not supportAC power supply; it is designed to operate exclusively onDC power.

Here’s an overview of the options:

OSN 9800:Supports both AC and DC power supplies, making it suitable for diverse deployment scenarios.

OSN 1800 II:Supports both AC and DC power supplies, providing flexibility for different environments.

OSN 1800 I:Designed for compact, cost-effective deployments, it supports onlyDC power, which may limit its use in certain scenarios.

OSN 1800 V:Supports both AC and DC power supplies, catering to high-capacity metro and access networks.

The lack of AC power support in the OSN 1800 I makes it less versatile compared to other models in the series.