Glossary
Terms that appear throughout this documentation, and in your meter's own manual.
Metering
OBIS code : Object Identification System. The standard identifier for a metering value, written A-B:C.D.E*F — for example 1-0:1.8.0 is positive active energy, total. Defined in IEC 62056-61. See Meter readings.
IEC 62056-21 : The standard covering the optical interface and the ASCII protocol used over it. Defines modes A to E. Sometimes still referred to by its old name, IEC 1107.
DLMS/COSEM : Device Language Message Specification / Companion Specification for Energy Metering. The structured protocol used by most modern smart meters. Objects are requested individually by OBIS code and interface class. See Meter protocols.
Mode A – E : The five IEC 62056-21 communication modes. C is the most common; D is one-way; E can hand the session over to DLMS.
LLS : Low Level Security. DLMS authentication with a shared password.
HLS / GMAC : High Level Security. DLMS challenge-response authentication using an authentication key.
GUEK : Global Unicast Encryption Key. The 16-byte block cipher key used to encrypt DLMS payloads.
AK : Authentication Key. The 16-byte key used to authenticate DLMS payloads, and for High/GMAC authentication.
Interface class : In DLMS, the type of a COSEM object. 1 = Data, 3 = Register (a value with a unit), 8 = Clock.
Tariff register : A sub-total covering part of the day. 1.8.1 and 1.8.2 are day and night sub-totals of 1.8.0; adding both to a total double-counts.
Summation delivered / received : Cumulative energy imported from and exported to the grid. Export is only reported by meters that measure it — typically where solar PV is installed.
Radio and network
Zigbee : A low-power wireless mesh protocol on IEEE 802.15.4 at 2.4 GHz. See Zigbee reference.
ZCL : Zigbee Cluster Library. The catalogue of standard clusters and attributes. ZiggyMeter implements v8 clusters only — nothing manufacturer-specific.
Cluster : A group of related Zigbee attributes and commands, identified by a 16-bit ID. Metering is 0x0702; Electrical Measurement is 0x0B04.
Endpoint : An addressable sub-unit of a Zigbee device. ZiggyMeter has two: endpoint 1 for the device, endpoint 2 for meter data.
Coordinator : The device that creates and manages a Zigbee network — a hub, or a USB adapter running software such as Zigbee2MQTT or ZHA.
End Device : A Zigbee node that does not route traffic for others and may sleep. ZiggyMeter is one.
Router : A mains-powered Zigbee node that relays traffic. Adding one between the meter and the coordinator often fixes range problems.
LQI : Link Quality Indicator. A coordinator's measure of Zigbee link quality.
RSSI : Received Signal Strength Indicator, in dBm. Closer to zero is better; worse than about −75 dBm is marginal.
PAN ID / Extended PAN ID : The 16-bit and 64-bit identifiers of a Zigbee network.
Permit join : The window during which a coordinator accepts new devices. It closes automatically after a few minutes.
ZHA : Zigbee Home Automation, Home Assistant's built-in Zigbee integration. See Home Assistant via Zigbee.
Access Point (AP) mode : The device hosting its own Wi-Fi hotspot rather than joining one. Always at 192.168.4.1. See Wi-Fi setup.
Client / station mode : The device joined to your own Wi-Fi network, with an address from your router.
Captive portal : The mechanism that makes a phone open a setup page automatically after joining a hotspot. Detection is unreliable; typing the address always works.
Device
OTA : Over The Air. A firmware update delivered wirelessly — over Wi-Fi or Zigbee. See Firmware upgrade.
Rollback attack : Installing an older firmware version to reintroduce a fixed vulnerability. ZiggyMeter refuses downgrades to prevent this.
Deep sleep : The low-power state the device enters between readings on battery power. LEDs are off and the device does not answer on the network.
Factory reset : Restoring defaults: clears Wi-Fi credentials, Zigbee pairing and the administrator password. Firmware is unaffected. See Button and LEDs.
Challenge-response : The login mechanism that proves knowledge of a password without transmitting it. See REST API.
Long-lived access token : A Home Assistant credential that does not expire, created in your user profile. ZiggyMeter uses one to publish sensors. See Home Assistant native integration. ZiggyMeter can also issue its own long-lived tokens for access to its REST API. See System.