information immediately to the host system, once.
Mode #2 - [M2] Polled Operation
This mode also continually scans the Reader for Tag reads, but stores the data for
subsequent retrieval when requested by the host computer. Due to limited processor
memory, only two Tags can be buffered by the Interface, therefore, care must be taken
to ensure that the Interface is polled frequently enough that no Tags are missed because
of full buffers. To request this stored information use the command the Transfer
Request Command.
Mode #3 - [M3] Report Duplicate Tags
This Mode continually scans for Tag reads via the Reader and transfers the information
immediately to the host system, repeatedly, as long a Tag is detected in the
Reader/Read Head’s signal field. The only exit from Mode 3 is via the System Reset
command or by cycling power.
The default Mode is set during Reset or Power Up according to jumper M2 at PCB address P3. The
default mode may be changed via these commands.
TRANSFER REQUEST COMMAND - [T]
Type this: [T]
The Transfer Request is used in Mode 2 to instruct the Interface to transmit a single
Tag's data. If a Tag has been detected since the last Transfer Request, its data will be
transmitted along with the Reader identifier in the standard format. If a Tag has not
been detected, an Empty Buffer message - "e" will be transmitted. It is recommended
that at least 70 milliseconds occur between Transfer Requests to allow the Interface to
search for Tags. It is also recommended that consecutive Transfer Requests be issued
until receipt of the "e" - Empty Buffer Message. The Interface keeps the last message
transmitted in its on-board memory in case a transmission error is detected by the host
and it requests a retransmission. Due to limited memory, this Tag retention takes up one
Tag buffer. Issuing subsequent Transfer Requests effectively acknowledges the
successful reception of the last Tag transmitted and frees up that memory for Tag data.
If received by the Interface while it is in Mode 1 or 3, the Transfer Request will cause a
"?" - Invalid Command message to be issued by the Interface.
BUFFER RESET COMMAND - [B####]
Type this: [B####]
The Buffer Reset Command allows the reporting of a previously reported Tag if re-
detected. In Modes 1 and 2, Tags are detected multiple times but reported only once
per detection at a given Reader. If the Tag is removed from the field for two seconds
or more, then re-introduced, it is re-reported without this command. This command
allows the same Tag to be re- reported at the designated Reader without being
removed for two seconds. The Readers are designated by the four hexadecimal
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