Updated Modem control using KISS protocol extension (markdown)

Modem-control-using-KISS-protocol-extension.md

@@ -35,6 +35,6 @@ Payloads for commands are sent and expected as big endian and defined as:
 
   // KISS command 9
   struct Telemetry {
-    int16_t batteryVoltage;
+    int16_t batteryVoltage;  // voltage * 100
   } __attribute__((packed));
 ```