notes

experiment/production/GPRS-GPS-notes.md

@@ -19,11 +19,11 @@ GPRS
 | 3.3v (1) | Vio (4) | Sets logic level, must be externally powered (RPi -> FONA) |
 | GND (6) | GND (3) | |
 | TXD (8) | RX (6) | RPi transmit -> FONA receive |
-| RXD (10) | TX (7) | RPi recieve <- FONA transmit |
+| RXD (10) | TX (7) | RPi receive <- FONA transmit |
 | GND (6) | Key (11) | Pulse 3-5s to ground to switch state (initially off) |
 
 `Key` is tied to the power button on the FONA.
-We want this to be permantly on without the need for
+We want this to be permanently on without the need for
 the Pi to turn it on or off, so this should be tied to ground (?).
 
 On the Raspberry Pi (RPi 3B+, Raspbian 2019-07-10 Buster)
@@ -132,6 +132,11 @@ is used for the GPRS modem.
 
 See [NMEA sentence information](http://aprs.gids.nl/nmea/) and the [AT command set](https://cdn-shop.adafruit.com/datasheets/SIMCOM_SIM5320_ATC_EN_V2.02.pdf).
 
+Connectors
+---
+
+I believe the two main connectors are IPEX 1 and SMA.
+
 References
 ---
 

experiment/production/Production-Overview.md

@@ -29,3 +29,22 @@ Software
   - Screensaver will light back up on press
 * Better screen diagnostics
 * Debug/testing of driver interface
+
+Progression
+---
+
+Instead of replacing the whole system in one iteration, I think
+it's better to replace certain components individually over time.
+
+The rough outline is as follows:
+
+* Replace the DIU with an updated piece of hardware
+  - If possible, a new case should be used but the old
+    case can be re-used if the need for replacement DIUs
+    is pressing
+  - There should be an old style connector for backwards
+    compatibility
+  - There should be a new style PIU and power connector.
+  - There should be either an adapter to connect to the old
+    style connector or have all connectors available
+