Using board level commands how would I connect(se​nd/receive messages) to an instrument​?

Question

I Have included the commands I typed at the prompt below. I used the "GPIB Messges Tutorial Development Libary" web page to guide me, however I don't get the results I expect out of "*IDN?" when I type "ibrd 100" I get an buffer is empty(see below). Do you know what I am doing wrong?
gpib0 ibic
ESP-488 in C for GPIB-ENET Interactive Test Program.
find gpib0 board
IBSTA: 0
IBERR: 0
IBCNT: 0
BOARD-> sic
IBSTA: 0
IBERR: 0
IBCNT: 0
BOARD-> cmd "@?\x22"
IBSTA: 0
IBERR: 0
IBCNT: 0
BOARD-> wrt "*IDN?"
IBSTA: 130
IBERR: 1
IBCNT: 0
BOARD-> wrt "*IDN?"
IBSTA: 0
IBERR: 0
IBCNT: 0
BOARD-> cmd "?SPB"
IBSTA: 0
IBE
RR: 0
IBCNT: 0
BOARD-> rd 100
Buffer =
IBSTA: 8130
IBERR: 3
IBCNT: 0
BOARD->

Answer 1

>> cmd "@?\x22"
-- This command sends MTA0, UNL(isten), MLA2.
This is correct if you wish to set the device at primary address 0 as a talker (likely your host computer) and the device at primary address 2 as a listener (likely your device)
>> cmd "?SPB"
-- This command sends UNL, MTA19, MTA16, MTA2
This is not correct. From the code, it appears that you want to set the device to be a talker and the host computer to be a listener. In this case, you would send
cmd "?\x42\x20" (anything with \x4 is a talk address, anything with \x2 is a listen addrress, so we have said UNL(isten), MTA2, MLA0)
In addition, you should only need to send the wrt "*IDN?" once.