Data request commands

This section lists valid commands to send over a Command Interface, either a virtual COM port or serial port, using a program such as TeraTerm or PuTTY-nd for instance. You may also want to use commands in Remote management commands and Dynamic configuration commands.

Note: When OSDP Secure mode is enabled on a particular Command Interface, ?b is the only valid data request command.

These commands request data stored in the VTAP reader without changing it in any way.

Note: End any command sent with a <CR> or <LF>, but not both.

A <setting> refers to any of those listed in config.txt settings .

Commands below: %<setting> | ?b | ?events | ?getserial | ?h | ?r | ?t | ?temp | ?type | ?uid

%<setting>

Definition:

Request the current value of any setting that could be included in the config.txt file.

API level: 0

Options:

Multiple settings can be requested in a single line command, by separating each setting with the | character.
Using % on its own will return all current settings.

Example value: %TagLED

?b

Definition:

Reads VTAP boot information including firmware version, API level and unique serial number.

API level: 0

Options:

Returns the BOOT.TXT data.
If OSDP is enabled on the port requesting this data (using OSDP interface settings) the data returned will also include 'OSDP:Enabled OSDP address: <OSDP_address_on_requesting_interface>' at the end.
If an OSDP Secure Channel is being enforced on the port requesting this data it will return 'OSDP:Enabled,SecureOnly OSDP address: <OSDP_address_on_requesting_interface>'

Example value: ?b

?events

Definition:

Polls for any events (such as configuration change) that have happened in the VTAP reader since it was last polled for events.

API level: 0

Options:

A 32-bit hex number supplied with the command is a bit mask to select only certain events be reported. The default without a bit mask is to report all events (equivalent to using bit mask ffffffff).

00000001 is returned by the command if the configuration has been updated (bit 0 set) since last poll.
00000004 is returned by the command if a reboot has taken place (bit 2 set) since last poll.
After reporting an event it is cleared.
If the bit mask used prevents the reporting of any event, it will remain pending for a subsequent poll.

Example value: ?events 00000001

?getserial

Definition:

Retrieve VTAP reader serial number, which appears in BOOT.TXT as 'VTAP label'.

API level: 0

Options:

Will return the serial number (VTAP label), or <NO SERIAL> if a serial number has not been set.

Example value: ?getserial

?h

Definition:

Retrieve public key hash information for the VTAP ECC keyslots, which can be used to work out which private keys have been loaded. The public key hash is the first 4 bytes of the 32 byte SHA-256 hash over the 32 byte ECC public key.

API level: 0

Options:

The block of public key hash data returned by the command is a 32 byte string.
The returned string starts with A5.
The public key data for the 6 key slots follows in order, 1 through 6.
Each key slot is described by a 1 byte flag (00=key slot empty, 01=key slot in use) then the 4 byte public key hash for that slot.
After all 6 keys the returned string ends with 5A.

Example value: ?h

?r

Definition:

Reads last NFC pass, card/tag data.
The tap data will be sent as long as it was read within the last InvalidDataCacheMS period and the request comes from an interface with a ...Source setting that permits this type of data to be sent over that interface.
Up to three serial interfaces can request and receive this cached data for a single tap, at different times, up to the InvalidDataCacheMS period. The data will not be overwritten by a more recent tap until all potential interfaces have read the tap data or the InvalidDataCacheMS period is reached. [Note: On hardware VTAP100 v4 or earlier, there is only one cache, so there is a greater risk that the data could be overwritten by a more recent tap before it has been read over all interfaces].

API level: 0

Options:

This is only used in passive mode (selected with ?p)

This command will only return pass/tag data where the ...Source setting for the interface requesting the data permits it.

Example value: ?r

?t

Definition:

Returns the type of the most recent cached NFC pass, card/tag read as a single character (as long as it was received inside the last InvalidDataCacheMS period) over the COM port.

API level: 0

Options:

Qualifiers instruct the VTAP to send an indicator of the type of NFC pass, card/tag data over a particular interface.

?t COM sends that NFC pass, card/tag data over COM port. (This is the default for ?t when an interface is not specified.

Returned values are pass types

(For a Pass type explainer - click here)

Example value: ?t COM

?temp

Definition:

Returns the internal temperature of the VTAP.

API level: 0

Options:

Returns a celsius value as reported by the processor.

Example value: ?temp

?type

Definition:

Returns the type of the most recent cached NFC pass, card/tag read as a single character (as long as it was received inside the last InvalidDataCacheMS period) over the COM port or serial port, in passive mode.

API level: 0

Options:

Returned values are pass types

(For a Pass type explainer - click here)

For Apple of Google passes the pass type is followed by VAS merchant ID/Smart Tap collector ID index and the key slot in use. In other cases -- follows the type.

Example value: ?type

?uid

Definition:

Reads last card/tag UID. (Up to 16 characters in hex format).

API level: 4

Options:

This is only used in passive mode (selected with ?p)

Example value: ?uid