New USB passthough question

Steven Catani

I have a sainsmart USB relay board I control via a small python program locally in the shack. I would like to be able to conroling using the new pass through feature as I seem to do most of my operating on my laptop now away ffrom the shack. When I configure the passthough based on the discussion it seems to set up correcty but the program soesn't work. It tells be there are not ftdi devices. My radio can switch the relays without any problem. Any ideas

Steven Catani

btw here is the pyhon code that works locally

import customtkinter as ctk
import ftd2xx
import os

RELAY_COUNT = 8
LABEL_FILE = "relay_labels.txt"

relay_labels = []
relay_states = [False] * RELAY_COUNT
buttons = []
ftdi = None

def load_labels():
labels = [f"Relay {i+1}" for i in range(RELAY_COUNT)]
if os.path.exists(LABEL_FILE):
with open(LABEL_FILE, "r") as f:
lines = f.readlines()
for i in range(min(RELAY_COUNT, len(lines))):
clean = lines[i].****()
if clean:
labels[i] = clean
return labels

def connect_ftdi():
global ftdi
try:
ftdi = ftd2xx.open(0)
ftdi.setBitMode(0xFF, 0x01)
status_label.configure(text="Connected to FTDI relay board")
turn_all_off()
for btn in buttons:
btn.configure(state="normal")
except Exception as e:
status_label.configure(text=f"FTDI connection failed: {e}")
for btn in buttons:
btn.configure(state="disabled")

def update_relay_outputs():
if ftdi:
mask = 0x00 # All OFF
for i, state in enumerate(relay_states):
if state:
mask |= (1 << i) # HIGH = ON
else:
mask &= ~(1 << i) # LOW = OFF
ftdi.write(bytes([mask]))

def make_toggle(relay_id):
def toggle():
for i in range(RELAY_COUNT):
relay_states[i] = (i == relay_id - 1)
buttons[i].configure(fg_color="green" if relay_states[i] else "gray")
update_relay_outputs()
return toggle

def turn_all_off():
for i in range(RELAY_COUNT):
relay_states[i] = False
buttons[i].configure(fg_color="gray")
update_relay_outputs()

ctk.set_appearance_mode("dark")
ctk.set_default_color_theme("blue")
app = ctk.CTk()
app.title("Antenna Relay Selector")
app.geometry("400x650")

relay_labels = load_labels()

for i in range(RELAY_COUNT):
btn = ctk.CTkButton(
app,
text=relay_labels[i],
fg_color="gray",
state="disabled",
command=make_toggle(i + 1)
)
btn.pack(pady=6, padx=20, fill='x')
buttons.append(btn)

status_label = ctk.CTkLabel(app, text="Not connected")
status_label.pack(pady=20)

connect_ftdi()

app.mainloop()

if ftdi:
ftdi.write(bytes([0x00])) # All relays OFF
ftdi.close()

Eric-KE5DTO

Sorry to be the bearer of bad news, but it looks like this script is talking directly to the FTDI drivers (e.g. not via the serial interface). As such, I'm don't think that this is going to work through the passthrough interface as what is exposed on the client side for passthrough cables is just a serial port (as opposed to a full USB device). I suspect this is why the script is complaining that there are no FTDI devices as this is accurate from the local point of view when the Sainsmart device is plugged into the radio.

Steven Catani

it seems the sainsmart cards that look exactly alike come with two different chips sets… one will except serial commands, the one I have onky excepts ftdi links with precludes the pass though…. looking at options