Physical Interface Decision - RS-422

DACI Decision

Recommendations

Contributors

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The people directly impacted by this so we can include them.
Any references to previous work and investigations that we can leverage.
Any constraints and challenges we need to consider to make this decision and following action plan.

Impact rating

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Decision characteristics
The decision will have a material impact on the customer experience OR will significantly impact the roadmap OR will adversely disrupt an internal business process.	HIGH
The decision will involve a less than material change to customer experience OR will impact the roadmap OR will impact an existing internal business process	MEDIUM
All other decisions	LOW

We need to select a physical layer standard for data communication between Oligo's bus and our payload.

	Option 1: RS-422	Option 2: RS-485	Option 3: LVDS
Description	A standard for serial communication allowing a single driver to connect to multiple receivers, using differential signaling for noise immunity.	An upgraded standard of RS-422 allowing for multiple drivers and receivers on a single bus.	A physical layer specification for high-speed, low-power digital interfaces, often used for video or high-bandwidth data transfer.
Rollout plan
Pros and cons	High noise immunity Long cable lengths Simpler timing that RS-485 Unidirectional (single driver only) Requires 4 wires for full duplex	True multipoint network High noise immunity Long cable lengths Requires software to handle bus turnaround to prevent data collisions	Extremely high data rates Very low power consumption (350 mV swings) Low EMI Point to point Requires strict and precise PCB routing Shorter cable lengths
Risks
Estimated cost and effort	Cost: Low Effort: Low	Cost: Low Effort: Medium/High	Cost: Medium/High Effort: High

Q1.

A1.

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