Answer
Yes, the SRQ line is a hardware line with the IEEE bus and this does not work with normal TCP/IP. So we cannot use it.
Because the calibration command is a query ‘CAL?’ we cannot send an additional query like ‘*OPC?’.
But we can use the same function as the Service Request uses.
The SRQ is triggered by the MAV bit (Message Available) in the Status Byte. I can query the Status Byte with a VISA function till the MAV bit is set (value 16) and then read out the buffer.
Here a log where I have done this: