Automating EXFO Instruments with SCPI: A Practical Guide

In today’s fast-paced world of telecom, datacom, and optical network testing, automation is no longer a luxury — it’s essential. If you’re using EXFO instruments like the NetBlazer, Power Blazer, or iOLM modules, mastering SCPI (Standard Commands for Programmable Instruments) can save you countless hours and unlock powerful test workflows.

🌟 What is SCPI?

SCPI (pronounced "skippy") is an industry-standard language for controlling test instruments. It’s a set of human-readable text commands that allow you to remotely:

Configure settings
Start and stop measurements
Fetch test results
Handle errors and statuses

If you’ve ever typed *IDN? to query a device’s identity, you’ve used SCPI!

📊 How EXFO Instruments Use SCPI

EXFO platforms like the FTB-1 Pro, FTB-2 Pro, and FTB-4 Pro, along with modular instruments like the FTBx-88480 (Power Blazer) or FTBx-8880 (NetBlazer), support SCPI over TCP/IP or Telnet sessions.

Each inserted module (called a "slot") is addressed logically using a LINSx ID, like LINS0, LINS2, etc. This allows you to direct SCPI commands specifically to the correct module, even if multiple instruments are present.

Before sending any commands, you should:

Discover available modules using STATUS MODULE
Connect to the desired LINS if needed using CONNECT LINSx

🌐 Basic SCPI Commands for EXFO

Here are some of the most important SCPI commands you need to know:

Command	Purpose
`*IDN?`	Query the instrument identification
`*RST`	Reset the module to factory default settings
`*CLS`	Clear the event and error queues
`STATUS MODULE`	List all available modules and their LINS IDs
`CONNECT LINSx`	Connect to a specific module
`LINSx:SOUR:DATA:TELecom:TEST:TYPE RFC2544`	Configure a test type
`LINSx:SOUR:DATA:TELecom:TEST`	Start the test
`LINSx:SOUR:DATA:TELecom:TEST:STOP`	Stop a running test
`FETCh:DATA:TELecom:RFC2544:SUMMary?`	Fetch RFC 2544 summary results

These basic commands let you fully automate test cycles from initialization to result collection.

🚀 Simple Python Automation Example

Controlling EXFO devices from Python is easy using raw TCP sockets. Here’s a basic example:

import socket

def send_scpi_command(command):
    ip = "192.168.1.100"
    port = 5025
    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
        s.connect((ip, port))
        s.sendall((command + "\r\n").encode())
        response = s.recv(4096).decode()
        return response.strip()

# Example usage
print(send_scpi_command("*IDN?"))
print(send_scpi_command("STATUS MODULE"))

For production-grade scripts, you’d want to handle timeouts, retries, and errors more gracefully, but this gives you a functional starting point.

🎓 Pro Tips for SCPI with EXFO

Always use STATUS MODULE before sending commands to ensure your LINS exists.
Use *CLS before starting new tests to avoid unexpected errors.
After starting a test, poll LINSx:SOUR:DATA:TELecom:TEST? until it reports "COMPLETED" before fetching results.
Handle error messages like "Index out of bounds" carefully — it usually means you sent a command to a non-existent object.

🌍 Conclusion

SCPI opens the door to powerful automation with EXFO’s field-proven instruments. Whether you’re validating metro Ethernet networks, mobile backhaul links, or datacenter fiber, automating your test setups can drastically improve efficiency and consistency.

Mastering just a handful of SCPI commands gives you full control over test configuration, execution, and reporting.

Stay tuned for the next post where we’ll build a complete Python SCPI test controller for EXFO platforms!

Happy testing! 🚀