FAQ

Next-generation 800G and 1.6T optical transceivers draw substantial power—often 20W to 30W+ per port.

• Passive loopbacks supports uptot 45W+ power spots with programmable function (from 0W- 45W) that can test maximum system loads.

• DSP Active Loopbacks combine the actual power consumption of the DSP chip (13W ~ 19W max.) with programmable power spots (23W max.). This allows data center engineers to stress-test fan speeds, power supply limits, and chassis airflow under simulated 100% full-power transceiver loads across all faceplate ports simultaneously. 

At 1.6T (8x200G), high-frequency attenuation over switch PCB traces causes severe eye closure before the signal even reaches the port faceplate.

• A passive loopback doubles the channel distance (host-to-port and port-to-host), causing total link failure due to combined insertion loss. and also with programmalbe power for port validation 

• A DSP active loopback acts as a retimer at the port edge. It cleans up distorted signals coming from the host switch ASIC, calculates link Bit Error Rates (BER) via its internal DSP engine, and sends a regenerated, clean signal back into the host. This enables engineers to isolate whether link issues stem from the host ASIC/board design or the optical transceiver.

• Architecture: Utilizes direct copper trace loops inside the module shell without active silicon.

• Function: Simply routes the electrical output from the host TX directly back into the host RX.

• Primary Use Case: Port trace continuity verification, basic low-power I2C/EEPROM handshake validation, and baseline link detection where host channel loss is negligible.
• Programmalbe Power consumption: Upto45W+ 

DSP-Based Active Loopback Module (ALB): 

• Architecture: Houses an onboard PAM4 DSP chip (major from Marvell / Broadcom) along with programmable microcontrollers.

• Function: Actively terminates the host 112G/224G SerDes signals, performs Clock and Data Recovery (CDR), RX Equalization (CTLE/FFE/DFE), and TX Pre-Emphasis, re-transmitting clean PAM4 signals back to the host.

• Primary Use Case: Full high-loss host channel validation (overcoming 10dB–30dB+ PCB trace loss), real-world thermal/power profiling (simulating 20W–40W+ optics), and complex CMIS 5.x runtime state machine negotiation

A Module Compliance Board (MCB) acts as the test fixture for optical transceivers, Active Optical Cables (AOCs), or Direct Attach Copper (DAC) modules. The optical or copper module inserts directly into the MCB’s cage.

• Primary Function: Validates the module's electrical interface, power rail noise immunity, and host-to-module signal paths.

• Management & Control: Equipped with control interfaces to read, write, and verify CMIS (Common Management Interface Specification) registers, power consumption, and I2C/MDIO communication.

A Host Compliance Board (HCB) is a precision test fixture designed to plug directly into host switch or line card ASIC ports (e.g., OSFP/QSFP-DD slots). It breaks out high-speed TX and RX electrical channels into standard coaxial RF connectors.

• Primary Function: Isolates and evaluates the host switch port's transmitter output, receiver jitter tolerance, and signal integrity without adding host-side cable distortion.

• Key Feature: Engineered with ultra-low insertion loss PCB materials and strict trace-length matching to adhere to IEEE and OIF compliance specs.

  A Host Compliance Board (HCB) is a precision test fixture designed to plug directly into host switch or line card ASIC ports (e.g., OSFP/QSFP-DD slots). It breaks out high-speed TX and RX electrical channels into standard coaxial RF connectors.

• Primary Function: Isolates and evaluates the host switch port's transmitter output, receiver jitter tolerance, and signal integrity without adding host-side cable distortion.

• Key Feature: Engineered with ultra-low insertion loss PCB materials and strict trace-length matching to adhere to IEEE and OIF compliance specs.