## Link Speed and Duplex Mode (Optional)

| CAUTION: By default the PRO/100 adapter is set to Auto Detect mode. This setting is correct if the adapter's link partner is also set to auto negotiate. If the adapter's link partner is not set to auto negotiate, but instead is set to a specific speed/duplex, the Link Speed & Duplex setting on the adapter will need to be changed so that it matches the setting on its link partner. However, manually forcing speed and duplex should be done by experienced network administrators only.

The Link Speed and Duplex setting lets you choose how the adapter sends and receives data packets over the network.

The possible settings for Link Speed and Duplex are:

- Auto Detect (requires a link partner set to auto-negotiate). The adapter negotiates with the link partner to send and receive packets at the highest rate. This is the default setting for the adapter. If the link partner is not set to auto-negotiate, the adapter runs at half duplex.

- 10Mbps or 100Mbps Full duplex (requires a full duplex link partner set to full duplex). The adapter can send and receive packets at the same time. This mode must be set manually (see the following sections).

- 10Mbps or 1000Mbps Half duplex. (requires a link partner set to half duplex). The adapter performs one operation at a time; it either sends or receives. This mode must be set manually (see the following sections).

NOTE

: If an adapter is running at 100 Mbps and half duplex, your potential bandwidth is higher than if you run it at 10 Mbps and full duplex.

### Manually Configuring for Full Duplex

If your link partner supports auto-negotiation with the NWay* standard, duplex configuration is automatic and no action is required on your part. Not all switches support auto-negotiation. Check with your network system administrator to verify whether your switch supports this feature. Most installations require manual configuration to change to full duplex.

Configuration is specific to the driver you’re loading for your network operating system (NOS).

To set a specific Link Speed and Duplex mode, refer to the section below that corresponds to your operating system.

CAUTION

: Adapter performance may suffer or your adapter may not operate if your link partner doesn’t support full duplex and you configure the adapter to full duplex. The link partner settings must always agree with the adapter.

### Setting Link Speed and Duplex in Windows 95/98/NT/2000

While running Windows:

> 1. Double-click the PROSet II icon from the Control Panel.

> 2. Click the Advanced Tab.

> 3. Select Link Speed and Duplex.

> 4. In the Link Speed and Duplex list box, click the speed and duplex mode appropriate for your adapter and its link partner.

> 5. Click OK.

> 6. Restart your computer if prompted.

### Setting Full Duplex in DOS, ODI, NDIS 2.01 Clients

For each adapter, edit the NET.CFG or PROTOCOL.INI file. If editing the NET.CFG file, add the following keywords to the Link Driver section. For the PROTOCOL.INI file, add these keywords anywhere:

FORCEDUPLEX 2

SPEED 100 (or 10 if 10BASE-T)

### Setting Full Duplex in NetWare Servers

For each adapter in AUTOEXEC.NCF, edit the LOAD command and add the following options (you must include the equal sign for servers):

FORCEDUPLEX=2

SPEED=100 (or 10 if 10BASE-T)