Description:

Lot of 7x Pulse Electronics PE-21264 telecom signal transformers (audio/signal isolation transformers), 8-pin through-hole DIP module. These parts are used for galvanic isolation and impedance matching in telecommunications interfaces (commonly T1/CEPT/ISDN style line interface designs). Markings include “PE-21264”, “40N SEC B”, “9042-” code, and “CHINA”. Great for repair/restoration of legacy telecom/network equipment, or for labs needing transformer isolation in similar circuits.

Modern uses:

- Repair/maintenance of legacy T1/CEPT/ISDN and telecom interface hardware

- Signal isolation + impedance matching in communication circuits

- Isolation experiments and prototyping where a telecom-grade transformer is required

- Audio/industrial interface projects where galvanic isolation is needed (application-dependent)

Compatibility note:

Telecom/signal transformers are not generic drop-in parts. For substitution, match the exact MPN (PE-21264) whenever possible. If replacing with another transformer, confirm pinout, turns ratio, insertion loss/bandwidth, DCR, isolation voltage rating, and the intended standard (T1/CEPT/ISDN). Same 8-pin DIP footprint alone is not sufficient—verify specs against the circuit requirements.