|
|
|||
TITLE
|
|
||
TOPIC
This article describes how to use the LocalTalk Bridge or LaserWriter Bridge software to connect LocalTalk devices to an extended network.
DISCUSSION
- A software bridge requires the host computer to be on in order for any bridged LocalTalk devices to be available to the other side of the network. A hardware bridge does not depend upon a host computer to function.
- The performance of the host computer is affected when the software bridge passes information from one side of the network to the other. A hardware bridge does not affect the performance of any computer.
- A software bridge is practically unlimited in the number of LocalTalk devices it can bridge. A hardware bridge is limited by the number of ports it offers.
Apple LocalTalk Bridge enables a Macintosh computer (the host) to function as a bridge between a LocalTalk network and an Ethernet, token ring, or infrared network. It bridges all LocalTalk devices connected to the host, enabling devices on both sides of the network to see each other.
Apple LaserWriter Bridge functions similarly, but only bridges one LaserWriter- or LaserWriter 8-compatible Apple LaserWriter printer. It enables computers on the extended network to use the LocalTalk printer attached to the host computer. It may not work with third party printers compatible with Apple's LaserWriter drivers.
Installation
Both products are control panels to be placed in the Control Panels folder of the System Folder. If the standard Ethernet, token ring, or infrared network software is already installed, the control panel is the only software required. The control panels appear below in Figures 1 and 2, followed by an example of a small Ethernet and LocalTalk network suitable for bridging (Figure 3).
Figure 1: LocalTalk Bridge control panel
Figure 2: LaserWriter Bridge control panel
Figure 3: A network configuration suitable for bridging
Step One
Connect both networks to the host computer. The LocalTalk network should be connected to the printer port of the host. Important: Only the host computer should have the Bridge installed, and no other bridges or routers can exist on the LocalTalk network.
If using LaserWriter Bridge, make the LaserWriter to be bridged the first LocalTalk device on the chain. Other LocalTalk devices will be ignored.
Step Two
Open the Chooser from the Apple Menu. Ensure that AppleTalk is set to "Active," as shown in the lower-right corner of the Chooser window.
Step Three
Depending upon the version of Mac OS installed, use either the Network control panel or the AppleTalk control panel to configure the host computer for Ethernet, token ring, or infrared as appropriate. Do not configure for LocalTalk.
Step Four
Open the LocalTalk Bridge or LaserWriter Bridge control panel and click the "On" button to enable it. Restart the computer if instructed to do so. Depending upon which Bridge is installed, the LaserWriter printer or the LocalTalk network will now be bridged, but will remain so only while the host computer is up and running.
How It Works
In the example shown in Figure 3, the LocalTalk printer and computer appear as regular Ethernet devices to computers on the Ethernet side of the network.
To configure for printing to the LocalTalk printer from any computer, proceed as normal, by first selecting the printer driver from the Chooser's icon list, then its name from the device list on the right. If the network has multiple zones, the printer will appear in the same zone as the host computer.
To connect to a shared LocalTalk volume (LocalTalk Bridge only), select AppleShare from Chooser's icon list, then the shared volume name from device list on the right. If the network has multiple zones, the LocalTalk volume will appear in the same zone as the host computer.
Public mode
LocalTalk Bridge: Computers on both sides of the network can see each other and all networked printers.
LaserWriter Bridge: The LocalTalk LaserWriter printer can be seen by all computers on both sides of the network.
Private mode
LocalTalk Bridge : Computers on the LocalTalk side can see both sides of the network, but the other side cannot see the LocalTalk side.
LaserWriter Bridge : The LocalTalk LaserWriter printer can be seen only by the host computer and computers on the LocalTalk side of the network.
Important Compatibility Issues
Versions of LaserWriter Bridge and LocalTalk Bridge prior to 2.1 are not compatible with Open Transport, and version 2.1 is not fully compatible with Mac OS 8.5 and later. There are no plans as of this writing to update either product. As a possible workaround to the Mac OS 8.5 compatibility issue, users are advised to first disable the bridge control panel and restart before switching network settings in the Network or AppleTalk control panels. Those looking for a compatible solution are advised to obtain a hardware bridge or a compatible software bridge from another manufacturer.
Software Bridges Versus Hardware Bridges
Hardware bridges compare with software bridges as follows:
A number of hardware and software bridge solutions are listed in the Mac OS Software & Hardware Guide at:
http://www.macsoftware.apple.com/