---
name: "umb"
section: "4"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["freebsd", "openbsd"]
url: "https://new.carta.tech/umb"
---

# umb(4)

USB Mobile Broadband Interface Model (MBIM) cellular modem driver

## NAME

**umb** – USB Mobile Broadband Interface Model (MBIM) cellular modem driver

## SYNOPSIS

**device usb** **device umb**

In [loader.conf(5)](/loader.conf/5.md): **umb\_load="YES"**

## DESCRIPTION

The **umb** driver provides support for USB MBIM devices. If the appropriate hardware is detected, the driver will be loaded automatically by [devmatch(8)](/devmatch/8.md). To load the driver manually, **load** it in [loader.conf(5)](/loader.conf/5.md) or at the [loader(8)](/loader/8.md) prompt.

MBIM devices establish connections via cellular networks such as GPRS, UMTS, and LTE. They appear as a regular point-to-point network interface, transporting raw IP frames.

Required configuration parameters like PIN and APN have to be set with [umbctl(8)](/umbctl/8.md). Once the SIM card has been unlocked with the correct PIN, it will remain in this state until the MBIM device is power-cycled. In case the device is connected to an "always-on" USB port, it may be possible to connect to a provider without entering the PIN again even if the system was rebooted.

## HARDWARE

The **umb** driver should support any USB device implementing MBIM, including the following cellular modems:

- Ericsson H5321gw and N5321gw

- Fibocom L831-EAU

- Medion Mobile S4222 (MediaTek OEM)

- Sierra Wireless EM7345

- Sierra Wireless EM7455

- Sierra Wireless EM8805

- Sierra Wireless MC8305

## SEE ALSO

[intro(4)](/intro/4.md), [netintro(4)](/netintro/4.md), [usb(4)](/usb/4.md), [ifconfig(8)](/ifconfig/8.md), [umbctl(8)](/umbctl/8.md) *Universal Serial Bus Communications Class Subclass Specification for Mobile Broadband Interface Model*, http://www.usb.org/developers/docs/devclass\_docs/MBIM10Errata1\_073013.zip.

## HISTORY

The **umb** device driver first appeared in OpenBSD 6.0, NetBSD 9.0, and FreeBSD 15.0.

## AUTHORS

The **umb** driver was written by Gerhard Roth ⟨*gerhard@openbsd.org*⟩ and ported from OpenBSD by Pierre Pronchery ⟨*khorben@defora.org*⟩.

## CAVEATS

The **umb** driver does not support IPv6.

Devices which fail to provide a conforming MBIM implementation will probably be attached as some other driver, such as [u3g(4)](/u3g/4.md).