The "T" and "N" suffixes in the part numbers indicate fundamental distinctions, typically representing different pull ranges or tuning characteristics within the CTS product line. Although the datasheets may not explicitly specify the Absolute Pull Range (APR), these letter codes effectively differentiate the voltage‑frequency curve slope, linearity, or tuning voltage range. For instance: - The "T" version may correspond to a specific tuning voltage range (e.g., 0–3 V) or offer better linearity; - The "N" version may exhibit different pull sensitivity (e.g., Hz/V) or tuning polarity. If the circuit relies on the VCXO’s voltage‑control characteristics—such as in a phase‑locked loop (PLL)—substitution could result in deviations in frequency lock range, loss of lock, or clock synchronization failure. Even if the base frequency matches, differing tuning curves may prevent the control voltage from achieving the desired frequency offset. In high‑speed communication or timing‑critical systems, this mismatch can introduce signal integrity risks.