TransCore encompass 4 - Command Mode

Encompass 4 Reader System Guide
7-4
Note: The Encompass 4 Reader transmits ID code
s to the host computer when the
Encompass 4 Reader is in data mode. If the Encompass 4 Reader remains in the com-
mand mode with tags passing through the read zone, all tag IDs are not reported.
Command Mode
While the Encompass 4 Reader is in the command mode, the host computer sends
commands to the Encompass 4 Reader that can be used to control the operation and
configuration of the reader. After the Encompass 4 Reader receives a command, it
transmits a command response message. Typically, the command message
contains Error, Don
e, or data relating specifically to the command request. These
messages may be of variable length since some commands require information as part
of the message; for example, Display Wiegand Mode Status.
Communications can be lost if the hos
t computer attempts to send certain commands
under marginal communications conditions. For example, if the host computer trans-
mits the command request to change the baud rate
and the Encompass 4 Reader prop-
erly receives the request and transmits the
Done message, one of the two following
conditions may occur:
• If the host computer receives the Done message, then both the host and the
Encompass 4 Reader switch to the new baud rate, and communications are main-
tained.
Note: In many applications, the host must
be set to the new baud rate as it will not
change automatically.
Note: The Enc
ompass 4 Reader changes the baud rate immediately after issuing the
Done message.
• However, if the host does not receive the Done message transmitted by the
Encompass 4 Reader, the host assumes that the command was not properly sent
and does not switch to the new baud rate, causing a loss of communications.
Caution
The host computer should not attempt to change communications parameters or
protocols during marginal communications
conditions; otherwise, a loss of commu-
nications can result.
Download Mode
In download mode, the Encompass 4 Reader allows the host to download new soft-
ware.
While in download mode, the reader communications port parameters
are fixed at the
following factory-default settings: 38400 baud, 8 data bits, 1 stop bit, no parity, soft-
ware flow control (XON/XOFF), basic protocol.
While in download mode, the Encompass 4 Reader turns RF of
f, does not process