JSON Data Structures

The communication protocol that is used to transfer data directly between the ENGAGE family of devices and the database host device is based on the JSON file format. The database host can be any device that connects to an ENGAGE device through an Ethernet, WiFi, or Bluetooth Low Energy (BLE) connection. This section defines all possible JSON tags that are used to configure an ENGAGE device, however tags are not applicable to all system configurations or devices. Tags which are utilized only in either the ENGAGE Gateway or ENGAGE API may be defined only in the ENGAGE - SAM API Integration documents.

Within the data structure tables, there are parent tags which do not include any data elements. Parent tags are implemented because they allow for the re-use of common tag names within a different parent tag context. An example of a common tag name is the tag “days”. This tag is common to the credential schedule and auto unlock parent tags. Another example is within the user records data structure. The “add”, “update” and “delete” parent tags share parameters that are specific elements with an individual user record. Parent tags within the tables are shown in Bold Text to differentiate from Child records.

For information regarding the JSON standard, the web site www.json.org contains many helpful links. The JSON specification can also be found at this link: http://www.ecma-international.org/publications/files/ECMA-ST/ECMA-404.pdf.

Device Messages

There are four (4) main categories for JSON data structures that are sent to and from a host system (access control panel or SW system) and the security device located at the entryway (lock or other device). These categories are:

• Database 
• Configuration 
• Audit Trail 
• Asynchronous Events / Alerts 

Data transfers between a host and device will occur within a “session”. The session contains data that is formatted to the JSON specification. The JSON “files” are sent over BLE, WiFi, or Ethernet to an embedded device that has limited RAM. As a result, the JSON data files are written to the lock’s flash memory and parsed after the data transfer has completed.

NOTE: ENGAGE Edge devices support only standard English language ASCII characters less than 0x7F.

Last Modified: October 22, 2019