Yes, but with caveats. The open-source community has reverse-engineered the older ZTE 16-digit algorithm (pre-2013). You can find Python scripts on GitHub searching for "zte_16digit_unlock." Example snippet:
A “16-digit ZTE unlock code calculator” isn’t a single published formula – it’s model‑dependent and often kept non‑public for business reasons. Reverse‑engineered versions exist unofficially, but using them carries risks. If you still want to pursue it, search for tools specific to your exact ZTE modem model and firmware version. zte modem dongle unlock code calculator -16 digit-
The Ultimate Guide to 16-Digit ZTE Modem Dongle Unlock Code Calculators Yes, but with caveats