Jim, I assure you that JrComm 1.02a (the final release) works just fine under Workbench 1.3. I used it back in the day and still do in the present under Workbench 1.3. It works so well, that it is basically my go-to terminal software for that version of Workbench.
The OP mentioned ATalk III. That is another decent Workbench 1.3 compatible terminal program but has more limitations and less capability compared to JrComm.
The OP mentioned ATalk III. That is another decent Workbench 1.3 compatible terminal program but has more limitations and less capability compared to JrComm.