Board-dat/DPR/DPR1097-DAT/DPR1097-DAT.md
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@@ -54,3 +54,4 @@ The ZYBA hole locations are in a different position AND the order has changed to
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- [[DPR1097]]
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+- [differential-signal-dat]
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\ No newline at end of file
Shipment-dat/Shipment-DAT.md
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@@ -70,7 +70,7 @@ Normal Post, worldwide delivery
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## ref
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-- [[shipment-by-country]] - [[shipment-by-continent]]
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+- [[shipment-by-country]] - [[shipment-by-continent]] - [[express-pick-up-dat]]
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- [[remote-address-dat]] - [[hs-code-dat]]
Shipment-dat/shipment-express-dat/express-pick-up-dat/express-pick-up-dat.md
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@@ -3,6 +3,9 @@
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https://wwwapps.ups.com/pickup/schedule?loc=en_US
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+https://wwwapps.ups.com/pickup/schedule?loc=en_CN
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+
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+
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We partner with a shipping agent to secure the best shipping discounts on packages. Due to the high volume of shipments they handle, they consistently receive the best discounted shipping rates. This allows us to pass significant cost savings on to you. They are also very experienced in resolving all shipping issues and customs issues.
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Shipment-dat/shipment-express-dat/shipment-express-dat.md
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@@ -12,7 +12,7 @@
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- [[US-dat]]
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-
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+- [[express-pick-up-dat]]
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## ref
Tech-dat/Interface-dat/interface-dat.md
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@@ -43,7 +43,7 @@ RS232 to RS485 module - [[DPR1080-dat]]
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[[RS422-dat]] breakout
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-- [[DPR1097-dat]]
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+- [[DPR1097-dat]] - [[DPR1098-dat]]
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[[Serial-dat]] breakout
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Tech-dat/analog-dat/analog-dat.md
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- [[digital-dat]] - [[digitizes-dat]]
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+- [[analog-dat]]
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## analog video other digital ethernet
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Tech-dat/signal-dat/differential-signal-dat/differential-signal-dat.md
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+# differential-signal-dat
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+
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+## board
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+
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+- [[DPR1097-dat]]
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+
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+
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+## 🔍 Key Differences: RS-485 vs RS-422
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+
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+| Feature | RS-485 | RS-422 |
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+|------------------|------------------------|----------------------------|
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+| Driver count | Multiple drivers | One driver only |
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+| Receiver count | Up to 32 receivers | Typically up to 10 |
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+| Duplex mode | Half or full duplex | Full duplex (typical) |
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+| Biasing required | ✅ Yes (often) | ❌ Not usually needed |
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+| Termination | ✅ Yes (120Ω) | ✅ Yes (120Ω) |
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+
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+---
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+
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+### 🧠 MAX490 in RS-422 Setup
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+
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+- The **MAX490 can act as the driver or receiver** in an RS-422 setup.
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+- Ensure only **one driver is active** on the bus.
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+- Communication is **half-duplex only**, due to MAX490 design.
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+- For full-duplex RS-422, use a different transceiver (e.g., MAX491).
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+
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+## MAX490 for RS422
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+
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+
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+| Feature | RS-422 (with MAX490) | Notes |
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+|----------------------------|----------------------------------|--------------------------------------|
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+| Driver | 1 (only one MAX490 TX active) | Matches RS-422 spec |
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+| Receiver | Up to 32 (MAX490 supports 32 RX) | RS-422 typically supports 10 |
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+| Termination needed | ✅ Yes | 120 Ω between A and B |
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+| Biasing resistors needed | ❌ Usually not | Optional; only if line floats |
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+| Duplex Mode | **Half-duplex only** | MAX490 can't do full-duplex RS-422 |
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+
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+#### ✅ Termination Resistor:
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+- Use a **120 Ω** resistor between A and B at the **end of the cable**.
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+
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+#### ❌ Biasing Resistors:
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+- **Not required** in RS-422 because the single driver maintains a known state.
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+- Optional if you observe floating voltages or noise.
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+
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+
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+
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+## Pull-up and Pull-down Resistors for MAX490 (RS-485)
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+
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+The **MAX490** is a differential RS-485/RS-422 transceiver. While it does not require internal pull-up or pull-down resistors, **external resistors are typically used for bus biasing** to ensure known voltage levels when no device is actively driving the bus.
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+
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+### ✅ When Are They Needed?
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+
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+- When no device is guaranteed to drive the RS-485 bus (e.g., during idle periods).
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+- To avoid undefined logic levels on the differential lines A and B.
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+- Especially important in **multi-drop** configurations.
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+
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+---
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+
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+### 🛠️ Recommended Biasing Setup
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+
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+Typical resistor values:
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+
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+- **Pull-up on A**: 680 Ω to +5V
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+- **Pull-down on B**: 680 Ω to GND
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+- **Termination resistor**: 120 Ω between A and B (at both ends of the bus)
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+
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+---
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+
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+### 📘 Circuit Diagram
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+
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+ +5V
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+ |
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+ R1 = 680Ω
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+ |
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+ A -----------+------------------------------+--- RS-485 Bus
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+ | |
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+ Rterm = 120Ω Other devices
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+ | |
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+ B -----------+------------------------------+--- RS-485 Bus
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+ |
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+ R2 = 680Ω
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+ |
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+ GND
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+
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+### 🔍 Notes
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+
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+- MAX490 includes **receiver failsafe** features, but **external biasing is still standard practice**.
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+- In **point-to-point** setups, biasing might be optional but is still recommended for stability.
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+- In **multi-drop** (multi-device) RS-485 networks, biasing is essential for reliable communication.
Tech-dat/signal-dat/signal-dat.md
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+# signal-dat.md
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+- [[digital-dat]] - [[analog-dat]]
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+
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+
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+- [[differential-signal-dat]]
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+
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+