The Macintosh Office effort ultimately failed, and one of the two companies, Centram, decided to implement a similar system on their own.
[1] Apple's own file sharing solution, AppleShare, was not released until later, and unlike TOPS it required a dedicated server machine to run on, at least a Mac Plus.
[6] PCs generally lacked networking of any sort, and Centram addressed this problem by introducing a line of LocalTalk cards for the PC, along with a TOPS client.
The Zilog SCC powering the serial ports on the Mac used an internal 3.6864 MHz clock that could then be divided down to provide different standard bit rates.
However, the system also allowed the clock to be read from a pin in the serial port, giving rise to the possibility of faster speeds with the right external equipment.
They worked around this problem by supporting an emerging LocalTalk-to-Ethernet bridging standard known as "KIP", short for Kinetics Internet Protocol.
Dedicated KIP-supporting network bridges were available that stripped off the AppleTalk packaging, re-formed the IP packets inside, and sent them out over Ethernet.
One limitation of the TCP stack was that it did not support DNS, requiring users to type in IP addresses of the peers they wanted to communicate with.