There should be no problem sharing the EtherTalk NB Card between EtherTalk and
TCP/IP.
It is not clear whether you need many workstations or just one, and if many
workstations are required, whether you need distributed sessions on those
stations.
Depending on the number of workstations to be connected to the mainframe,
Tri-Data Netway 2000 from Tri-Data Systems is certainly a solution; however, it
might be overkill for one workstation.
Running MacDFT using the Coax/Twinax Card will work, but you will need to
connect to an IBM 3X74 controller. Running MacDFT 1.1 using the Serial NB
Card, you can have SNA connectivity to the host via a Front End Processor.
You can also run Avatar MacMainFrame 3.5 (from Avatar, Inc.) using Avatar
SNA/SDLC card and distribute the sessions to LocalTalk, EtherTalk, or
TokenTalk.
It is difficult to predict the traffic without knowing about the network
topology, the number of workstations, and the applications. Of the
applications you mentioned, MacX might be the one with the most traffic, but
this should be fine with one workstation.
For more information, search under: "DCA (formerly Avatar)" and "Tri-Data
Systems"
Article Change History:
26 July 1993 - Company title changed from Avatar to DCA (Digital Communication
Associates).
3 May 1990 - Updated for technical accuracy