Apple Macintosh System 7.5 - Manual (Page 30)

Depending on the AppleTalk network types in your organization, you may
need to upgrade to AppleTalk Phase 2 before installing System 7.5.
Network type What to do
LocalTalk No action is necessary.
TokenTalk No action is necessary.
EtherTalk Upgrade if using any version earlier than 2.0 of the EtherTalk driver.
Non-Apple Check with dealer or manufacturer.
The following sections describe the effect, for each AppleTalk network type,
of upgrading to System 7.5 from System 6.
If you are upgrading from version 7.0 or 7.1, you do not need to upgrade your
network.
LocalTalk networks
If your network uses only LocalTalk connections and does not have routers,
upgrading some computers to System 7.5 will have no effect on networking.
Although the new LocalTalk driver installed with System 7.5 is an AppleTalk
Phase 2 driver, the protocol changes in Phase 2 do not prevent communication
between Phase 1 and Phase 2 users on a LocalTalk network without routers.
If there is an Apple Internet Router 3.0 or later on your network, upgrading to
AppleTalk Phase 2 is recommended.
TokenTalk networks
If your network contains TokenTalk connections, these computers are already
using AppleTalk Phase 2. All TokenTalk drivers support AppleTalk Phase 2.
Upgrading to System 7.5 on Macintosh computers using TokenTalk will have
no effect on networking.
27 Planning the Group Upgrade