Communication Setup
Most Payter Session Protocol commands are restricted to a number of states. Which state is designated in each command definition. PSP generally however requires the Enabled status for most operational commands. This status is achieved via a number of sequential and optional commands, as shown below:
Several commands, not listed above, do NOT result in State changes. These are detailed below.
Commands Without State Changes
| Command Name | Command Header | Usage & Restrictions if applicable |
|---|---|---|
Remove Sessions | 0x56 | Only allowed in the Enabled state |
Get Status | 0x26 | Always allowed |
Protocol | 0x13 | Only allowed in the Online state |
Void Session | 0x33 | Only allowed in the Disabled, Enabled, Wait Card & Wait Auth/cancel state |
Commit session | 0x35 | Only allowed in the Disabled, Enabled, Wait Card & Wait Auth/cancel state |
UI Request | 0x40 | Only allowed in the Enabled, Wait Card & Wait Auth/cancel state.In the Wait Card & Wait Auth/cancel state the UI Request will be hidden from view and the last request is shown only after the payment flow releases its claim of the display. |
| Select Language | 0x40 | Always allowed |
Get Receipt | 0x45 | Only allowed in the Disabled, Enabled, Wait Card & Wait Auth/cancel state |