How to Tether a PC with Windows Mobile 6.5

Windows Mobile 6.5 provided native tethering capabilities that allowed users to share their smartphone's cellular data connection with a personal computer, turning the mobile device into an external modem. This feature primarily relied on the operating system’s built-in "Internet Sharing" utility, which facilitated wired USB or wireless Bluetooth connections. This article explains how the Internet Sharing application functioned, the protocols it used to connect to PCs, and how users navigated carrier restrictions and Wi-Fi limitations at the time.

The Internet Sharing Application

Windows Mobile 6.5 streamlined mobile broadband sharing using a dedicated application called Internet Sharing, which replaced the older, more complex Dial-Up Networking (DUN) setups found in legacy versions of the OS. The utility acted as a bridge between the phone's cellular data connection (GPRS, EDGE, 3G, or HSDPA) and the host PC.

To initiate tethering, the user configured two settings within the application:

  1. PC Connection: Set to either USB or Bluetooth.
  2. Network Connection: Selected the active cellular service provider APN (Access Point Name).

Once the user tapped "Connect," the phone established the mobile data link and began routing network traffic to and from the connected computer.

Connection Methods

1. USB Tethering (RNDIS)

USB was the most common and reliable method for tethering a PC via Windows Mobile 6.5.

  • When connected via a mini-USB or micro-USB cable, the phone utilized the Remote Network Driver Interface Specification (RNDIS) protocol.
  • Windows-based PCs automatically recognized the tethered phone as a virtual Ethernet network adapter rather than a serial modem.
  • The phone ran an internal Dynamic Host Configuration Protocol (DHCP) server, assigning a private IP address (typically in the 192.168.x.x range) to the computer.
  • This method supplied consistent speeds and kept the mobile device charged while routing data.

2. Bluetooth Tethering (PAN and DUN)

For a wireless connection, Windows Mobile 6.5 supported Bluetooth tethering via two profiles:

  • Personal Area Networking (PAN): Allowed the phone to act as a network access point, routing data over an ad-hoc Bluetooth network. This was the preferred wireless method for its ease of setup and stability.
  • Dial-Up Networking (DUN): Allowed legacy PCs to treat the phone as an external wireless modem, requiring the PC to dial an access number (such as *99#) to initiate the carrier data session.

Wi-Fi Hotspot Limitations and Third-Party Solutions

Windows Mobile 6.5 did not natively support Wi-Fi hotspot tethering (SoftAP mode), meaning users could not share their internet connection over Wi-Fi using only built-in OS tools.

To bypass this limitation, users turned to third-party applications such as WMWifiRouter. These utilities reconfigured the phone’s Wi-Fi chip from client mode to ad-hoc or access point mode, allowing multiple Wi-Fi-enabled devices to connect to the Windows Mobile cellular connection simultaneously.

Carrier Controls and Registry Modifications

Because mobile network operators during the Windows Mobile era often charged separate fees for tethering plans, many carriers disabled the Internet Sharing executable or hidden its menu entry via customized ROMs. Advanced users frequently bypassed these restrictions through Windows Mobile registry edits, modifying values under HKLM\Comm\InternetSharing to re-enable disabled connection types or prevent carriers from detecting tethered traffic.