User's Manual

28 MDS TransNET I/O Guide MDS 05-2708A01, Rev. A
If data buffering is set to OFF, the radio will operate with the lowest possible
average latency. Data bytes are sent out the DATA INTERFACE port as soon as
an incoming RF data frame is disassembled. Average and typical latency will
both be below 10 ms, but idle character gaps may be introduced into the
outgoing data flow.
If data buffering is
ON, the radio will operate in a seamless mode. That is, data
bytes will be sent over the air as quickly as possible, but the receiver will buffer
the data until enough bytes have arrived to cover worst case gaps in
transmission. The delay introduced by data buffering may range from 25 to 50
ms, but the radio will not create any gaps in the output data stream. This mode
of operation is required for protocols such as MODBUS™ that do not allow
gaps in their data transmission.
that seamless mode (
BUFF ON) is intended only for applications where the
transmitter’s baud rate is greater than or equal to the receiver’s baud rate.
Enforcement of this rule is left up to the user.
Changes to the
BUFF setting may only be made at the master radio. This is
because the master radio broadcasts the buffer setting for the entire network.
At remote radios, the buffer setting may be read when the radio is in
synchronization with the master, but it may not be changed.
CLOS
Table and information pending.
CTS [0–255]
The CTS (clear-to-send) command sets or displays the timer value associated
with the CTS line response. The command parameter ranges from 0 to 255
milliseconds.
For DCE operation, the timer specifies how long to wait after the RTS line goes
high before asserting the CTS line. A timer value of zero means that the CTS
line will always be asserted (unless the radio is attempting to throttle back data
as part of normal flow control operation).
For CTS Key operation (see the
DEVICE command), the timer specifies how
long to wait after asserting the CTS line before sending data out the DATA
INTERFACE port. A timer value of zero means that data will be sent out the
data port without imposing a key-up delay. (Other delays may be in effect from
other radio operating parameters.)
CTSHOLD [0-6000]
Used in DEVICE CTS KEY mode, this command sets the amount of time in
milliseconds that CTS remains present following transmission of the last
character out the RXD pin of the DATA INTERFACE port. This “hold time” can
be used to prevent squelch tail data corruption when interworking with other
radios.
The
CTSHOLD setting can range from 0 to 6000 (i.e., 6 seconds). The default
value is 0, which means that CTS will drop immediately after the last character
is transmitted. If the command is entered when the radio is in DEVICE DCE
mode, the response CTSHOLD N/A will be displayed.
DEVICE [DCE, CTS KEY]
The DEVICE command sets or displays the device behavior of the radio. The
command parameter is either DCE or CTS KEY.