7i97T + 7i74 + 7i84U – No Smart Serial Communication

Hi,I am retrofitting a CNC lathe with LinuxCNC and I have the following Mesa hardware:

• 1x Mesa 7i97T
• 1x Mesa 7i74
• 4x Mesa 7i84U
• IDC26 to DB25 adapter
• DB25 male-male 1:1 cable between 7i97T P2 and 7i74
• standard straight-through CAT5e cables between 7i74 and 7i84U

The problem is that none of the 7i84U boards are detected over Smart Serial.The 7i97T is reachable at:I am using firmware:MD5:I also verified the firmware in flash with:and I get:gives only:but no 7i84U devices are listed.I tested 7i84U boards on CH1 and CH2 of the 7i74 with the same result.On the 7i84U:

• W3 = LEFT / operate mode / 2.5 Mbaud
• VIN = about 28 V
• VFIELD A = about 28 V
• VFIELD B = about 28 V
• CR2 ON
• CR7 ON
• CR5 red ON
• CR6 green OFF / never blinks

On the 7i74:

• CR1 is ON
• I initially measured only about 4.5 V
• I changed it to external regulated 5 V supply
• now TB1 measures 5.08 V
• the problem is still exactly the same

I checked the RJ45 cable and it is straight-through:I also tested the 7i97T P2 interface with W21 UP and P2 disconnected:Result:So that test appears to pass. also shows the expected Smart Serial signals: on the 7i97T and  for the 7i74 channels.I also tried loading HostMot2 manually:The 7i97T loads and registers normally, but the 7i84U is still not detected.Everything is new hardware.At this point I suspect either the 7i74 itself, the IDC26/DB25 path between P2 and the 7i74, or something I am missing in the Smart Serial configuration.Does anyone have a known-good 7i97T + 7i74 + 7i84U setup and can tell me what I should test next?In particular:

• Is 

  sserial_port_0=x0xxxxxx

   correct for a 7i84U connected to CH1 of the 7i74?
• Is there a direct test for TX/RX on the 7i74 without an oscilloscope?
• Are there any jumpers/settings on the 7i74 or 7i84U that I may have missed?

Thanks.

I would try:

config="sserial_port_0=00000000"

Might also be a DB25 cable issue, not all adapters are wired correctly for this use.

I used this two cables for connection. 

eusurplus.com/index.php?route=product/pr...t_id=108&search=db25
eusurplus.com/index.php?route=product/pr...t_id=109&search=db25

Thank you for your answer.

I can try duplicating this later today.

ok. thank you very much