From 46f1d91a5c9c5fa86ed4e5d4f41aeb07b7d17565 Mon Sep 17 00:00:00 2001
From: Mark Thompson <129641948+NotherNgineer@users.noreply.github.com>
Date: Thu, 18 May 2023 17:51:51 -0500
Subject: [PATCH] Updated to mention support for SCM+ protocol (#907), and
 corrected description of type field

---
 ERT.md | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/ERT.md b/ERT.md
index 424af30..a4e2917 100644
--- a/ERT.md
+++ b/ERT.md
@@ -1,14 +1,16 @@
-[Encoder receiver transmitter](https://en.wikipedia.org/wiki/Encoder_receiver_transmitter) (ERT) is a packet radio protocol developed by Itron for automatic meter reading of water, gas and electricity. The system uses OOK short range radio which is transmitted in the unlicensed 900-920 MHz band, so that meters can be read from a passing vehicle. This is mainly used in USA. The data is not encrypted, and does not have functions to enable full control. The system is not as advanced as a smart meter and lacks the control or  security in the data transfered.
-ERT
+[Encoder receiver transmitter](https://en.wikipedia.org/wiki/Encoder_receiver_transmitter) (ERT) is a packet radio protocol developed by Itron for automatic meter reading of water, gas and electricity. The system uses OOK short range radio which is transmitted in the unlicensed 902-928 MHz ISM band, so that meters can be read from a passing vehicle. This is mainly used in USA. The data is not encrypted, and does not have functions to enable full control. The system is not as advanced as a smart meter and lacks the control or security in the data transferred. Supported message protocols are IDM, SCM, and SCM+.
 
 The Key Items on the App that can be selected with the cursor and changed with the encoder knob are:
 
 * **Title bar:** The usual Items may be changed and displayed.
 * **Gain:** Setting are shown in order of AMP 0=0db or 1=14dB, LNA(IF) (0-40) and VGA (Baseband Gain) (0-62).
-* **ID:** this is the meter ID.
-* **Tp:** This is the type of meter. 0=Unknown,1 =IDM, 2=SCM.
+
+Fields displays in the App are as follows:
+
+* **ID:** this is the meter ID (should match number/barcode printed on meter).
+* **Tp:** This is the type of meter as indicated in the message. (Likely meter type codes include Electric: 4, 5, 7, 8, 12;  Gas: 0, 1, 2, 9, 12;  Water: 3, 11, 13)
 * **Consumpt:** The Meter reading value.
-* **Cnt:** The count of the number of readings.
+* **Cnt:** The count of the number of readings with the same meter ID.
 
 The PortaPack ERT receiver monitors approximately 2.5 MHz centered around 911.6 MHz. It does not implement channel filters, so sensitivity is reduced in exchange for monitoring more simultaneous "channels".