# Integrated access device

> An integrated access device (IAD) is customer-premises equipment that combines voice interfaces, IP routing and WAN connectivity in one managed appliance. A modern cellular IAD can present analog FXS ports while carrying voice and data over LTE or 5G.

- Also known as: IAD, cellular IAD
- Last reviewed: September 1, 2026

## How it works

The IAD terminates the site's WAN link — historically a T1 or DSL circuit, today increasingly LTE or 5G — and splits it into the services the site consumes: analog voice on FXS ports, data on Ethernet LAN ports, and routing between them. Voice is digitized on the premises side and shares the access link with data traffic, with the IAD prioritizing voice packets so calls stay clear under data load.

## Why it matters

One managed appliance replaces a stack of single-purpose boxes — separate voice circuits, a router, and a modem — which is exactly the consolidation copper retirement forces. A site losing its POTS lines and its DSL in the same sunset can land both on a single cellular IAD instead of replacing them separately.

## Common use cases

- POTS line replacement with data service on the same appliance
- Branch-office voice and internet over one WAN link
- Fixed wireless access with analog line support
- Internet backup and cellular failover alongside voice

The term dates from the era when a business bought voice and data as one bundled T1. It has
outlived that circuit because the architecture keeps being right: one box, one WAN bill, and
one management plane for both services.

## IAD vs. ATA: what's the difference?

An [analog telephone adapter](https://dataremote.com/newsroom/definitions/analog-telephone-adapter) converts between
analog telephony and packets — [FXS](https://dataremote.com/newsroom/definitions/fxs) ports on one side, IP on the
other. That conversion is one component of an IAD, not the whole device. The IAD adds two
things a standalone ATA does not have: IP routing for the site's data devices, and
termination of the WAN link itself. Put simply, an ATA plugs into someone else's router; an
IAD *is* the router.

## IAD vs. voice gateway

A voice gateway translates between telephony domains — SIP trunks to analog lines, PRI to IP —
usually as one element inside a larger network, and it typically does not route the site's
general data traffic. An IAD faces the premises instead: it delivers the site's voice *and*
data over one access link. The categories overlap in practice, so the useful test is
functional: does one appliance terminate your WAN, route your LAN, and present your analog
ports? If yes, it is doing an IAD's job, whatever the datasheet calls it.

## IAD vs. cellular router

A data-only cellular router terminates a cellular WAN and routes Ethernet or Wi-Fi — and
nothing else. It has no FXS ports, no dial tone, no ring voltage, and no way to serve a fax
machine or an alarm panel. A [cellular gateway](https://dataremote.com/newsroom/definitions/cellular-gateway) with
true FXS telephony closes that gap; when it also routes the site's data, it is a cellular
IAD. For a site with analog devices, that distinction is the whole decision.

## Traditional T1/DSL IADs vs. modern LTE/5G IADs

| | T1/DSL era IAD | Modern cellular IAD |
| --- | --- | --- |
| WAN access | T1/E1 or DSL circuit | LTE or 5G, often dual-SIM |
| Voice transport | Channelized TDM or early VoIP | VoIP engineered to preserve analog behaviors — DTMF, ring-down, alarm formats — in supported configurations |
| Power resilience | Little or none on the IAD itself | Integrated battery backup, commonly up to 24-48 hours depending on model and load |
| Management | On-site configuration, per-unit | Remote fleet provisioning and line-status monitoring |
| Failure mode | Died with its circuit | The cellular path is itself the continuity plan |

The access technology changed; the consolidation logic did not. What changed most is
resilience: a T1 IAD went down with its circuit, while a cellular IAD with battery backup is
deployed precisely to survive circuit and power failures.

## How does an IAD support POTS replacement?

[POTS line replacement](https://dataremote.com/solutions/pots-line-replacement) succeeds or fails on the analog
side: the appliance must present RJ-11/FXS ports with the dial tone, loop current, DTMF, and
disconnect behavior legacy devices expect. A cellular IAD provides that while carrying the
calls over LTE or 5G — and because the same appliance routes data, it can simultaneously
serve as the site's [fixed wireless access](https://dataremote.com/solutions/fixed-wireless-access) connection or
its [internet backup path](https://dataremote.com/solutions/internet-backup-cellular-failover). One installation
replaces the copper voice lines and hardens the site's connectivity in the same visit.

## Which POTS IN A BOX® products are IADs?

The qualifying test is voice access plus customer data routing in one appliance:

- **[90X5](https://dataremote.com/pots-in-a-box/90x5)** — the fullest expression of the architecture: a modular
  gateway with Gigabit Ethernet routing, 4-8 FXS voice lines, and 5G RedCap WWAN with LTE
  fallback, in independently swappable modules.
- **[90X1](https://dataremote.com/pots-in-a-box/90x1)** and **[90X2](https://dataremote.com/pots-in-a-box/90x2)** — 8 FXS ports, Ethernet
  WAN/LAN, an optional wired NAT router with SD-WAN, and 5G or LTE cellular WAN with internet
  failover: modern cellular IADs optimized for POTS replacement.

The CDS-9090 and CDS-9010 also pair FXS voice with Ethernet and Wi-Fi routing for
larger-site and compact deployments, and the VAB-1 includes an integral router alongside its
8 plug-and-play lines. Capabilities vary by model — the product pages list each device's
interfaces and routing options.

## Common misconceptions

**Claim:** An IAD is the same thing as an ATA.

**Correction:** An ATA converts analog telephony to packets — that is one function inside an IAD. The IAD adds IP routing and WAN termination, so it serves the site's data devices as well as its phones. Every IAD contains ATA functionality; most ATAs are not IADs.

**Claim:** IADs disappeared with T1 circuits.

**Correction:** The access technology retired, not the architecture. An appliance that combines FXS voice, routing, and a cellular WAN is an IAD in every functional sense — the T1 interface has simply been replaced by LTE or 5G.

## Frequently asked questions

**Is a POTS IN A BOX® appliance an integrated access device?**

The models that combine analog FXS ports with IP routing and cellular WAN connectivity — the 90X5, 90X1, and 90X2 — function as modern cellular IADs. Capabilities vary by model and configuration; see each product page.

**Do I need an IAD or just a cellular router?**

If the site has any analog devices — phones, fax machines, alarm panels, elevator phones — a data-only router cannot serve them. An IAD carries voice and data together, so one appliance covers the site.

## Sources

- [Technology Transitions](https://www.fcc.gov/tech-transitions) — Federal Communications Commission


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Canonical page: https://dataremote.com/newsroom/definitions/integrated-access-device
Organization: DataRemote, Inc. — POTS line replacement, cellular failover, and fixed wireless access solutions. https://dataremote.com