The procedures you talk about can be used to communicate two calculators
Sorry, I began doing tests on this topic and confirmed that it is not possible to use Send38K/Receive38K to communicate two calcs

. What I tryed was:
1) Send38K Receive38k
In this case both programs end quickly. No results with reals neither lists
2) SendVar38K Receive38k
No results.
3) Send38K GetVar38k
Both programs end quickly, since, for some reason, Send38K causes GetVar38k to end, like if it accepted its format without complaining. No variable could be transfered nor any value.
I do have here an EA-200, and did a test with it using not the ECON-EA200 but a small program in the Cp300:
OpenComPort38k
{0}->a
Send38k a
{1,1,9}->a
Send38k a
{3,1,60}->a
Send38k a
Message "Now press the EA-200 [START/STOP] key. and wait for the sampling of the data."
Receive38k list1
Receive38k list2
Print list1
Print list2
CloseComPort38k
This program initializes the EA-200, sets up the optical probe, the total sampling time and the number of samples. It also return in two lists (viewable directly with the Statistics application) the time and values.
I could be of more help if I had the cable to monitor the serial comm between the calc and the EA-200. (I am working on that)
On the other hand, why is the long timeout of GetVar38k a problem.. In my test I ran the receiver prog and it kept waiting, when I ran the sender prog then the receiver progr ended immediatly.
I looked into the EA-200's manual. It comes with information related to other supported calcs like AFX and CFX. They say one should go to the calc's manual to see details of the comm functions.
Finally, in that manual there is a complete description of the protocol used by the EA-200. The only pending thing is to know how do Send38K/Receive38K work

.