# ARRIS (T25) - ケーブルモデム - 高速DOCSIS 3.1ギガビットケーブルモデム Comcast Xfinity インターネット&音声 2つの1Gbpsポート 800Mbps Xfinityプラン付き

> ARRIS (T25) summary. A DOCSIS 3.1 cable modem approved for Xfinity internet and voice at up to 800Mbps, with two 1Gbps Ethernet ports and two FXS phone ports. Bring your own router and cut the rental fee.

Tags: modem, arris, surfboard-t25, docsis-3-1, xfinity
Source: https://www.amazon.co.jp/dp/B07MGPPNZD
Article page: https://web-autoai.com/articles/arris-t25-docsis-31-comcast-xfinity-21gbps-800mbps-xfinity?lang=en

Prices and ratings change over time — check the article page for the current values.

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This article covers ARRIS (T25).

## Overview
The ARRIS SURFboard T25 is a DOCSIS 3.1 cable modem certified for Comcast Xfinity internet and digital voice service. It packs two 1Gbps Ethernet ports and two telephone ports into a standalone box, so households on Xfinity plans of up to 800Mbps can replace a rented gateway with hardware they own.
The modem does not include Wi-Fi, which is actually an advantage if you already own a good router or mesh system. You can put the T25 at the edge of your network, connect your own router to one of the Gigabit ports, and use the second port for a wired PC or NAS. With a large installed base of cable modems behind the brand, ARRIS is a familiar name in this category, and the T25 continues that legacy in a simple modem-only form.

## Connectivity & Compatibility
Setup is straightforward: attach the ISP's coax cable to the rear connector, plug in the power adapter, then run Ethernet from the modem to your router. Because the T25 is not a router or gateway, you need an external Wi-Fi router for wireless coverage. That clean separation between modem and router reduces the chance of double NAT and keeps IP address handling more predictable.
Compatibility is limited to Xfinity internet and Xfinity voice service, and the modem is approved for cable internet plans up to 800Mbps. The two FXS phone ports let you connect analog phones to Xfinity's digital voice service. Note that this is a US-market product, so it will not work with Japanese fiber optic or cable internet providers; it is only a practical choice for someone on the supported US service.

## Product Info
The T25 sits in the entry-to-mid tier of standalone DOCSIS 3.1 modems. It deliberately leaves out routing and Wi-Fi to keep the cost down and to serve households that already have networking gear. That is a different trade-off from a Wi-Fi gateway, but it is exactly what you want when building a dedicated modem-to-router chain.
Over a year or two, however, the savings from canceling a modem rental can offset that difference. Warranty coverage depends on the seller, so check the support policy carefully before buying an import unit.

## Best Use Cases
Xfinity customers who want to stop renting the provider's gateway and cut monthly bills will benefit the most; the T25 handles both internet and digital voice in a single unit.
Households that already run their own Wi-Fi router or mesh setup are also a great fit, since the T25 does not duplicate routing functions and lets you keep your preferred router settings.
Users who need more than one physical phone line can take advantage of the two FXS ports to connect two analog handsets.
The T25 is not suited for Japanese ISPs or most non-Xfinity providers, so verify your provider's compatibility list before buying.

### Product Disclosure (Amazon)
- Manufacturer: ARRIS
- Seller: ZENKI オンラインストア
- Fulfilled by: ZENKI オンラインストア
- ASIN: B07MGPPNZD
- Note: This article covers a manufacturer-made product based on Amazon listing details.