58
SD Series Technical Manual
MDS 05-4846A01, Rev. H
NOTE:
The lower the value of the Maximum Wait Time, the higher
the chances of collisions occurring over-the-air. Conversely,
the higher the value of the Maximum Wait Time, the higher the
transmission latency.
•
Timeout (ms)
—Provides a setting for the maximum wait time (in
milliseconds) for the channel to become free. When this time is
exceeded, the radio follows the action defined in the
Packet Action
on Timeout
setting (either
Drop
or
Send
).
•
Packet Action on Timeout
—Determines what to do with a packet once
the timeout period has expired and the channel is still not avail-
able. If set to
Drop
, the packet is discarded. If set to
Send
, transmis-
sion of the packet is attempted despite the channel being busy.
•
Clear Channel RSSI (dBm)
—LBT works by sensing the presence of a
carrier signal on the radio’s operating frequency. If a carrier is
present, transmission is inhibited. The
Clear Channel RSSI
setting
allows a threshold to be set which, when equaled or exceeded,
declares the channel busy and therefore unavailable for transmit-
ting.
IP Payload
Configuration (1/2/3)
This section describes how to setup and configure the Master radio for
exchanging IP/Ethernet Payload data with Remote radios. It is an effi-
cient feature that supports Ethernet connectivity with maximum
over-the-air (OTA) efficiency for UDP and TCP data streams. Remote
radios receiving the data can then forward this traffic to their serial ports
or Ethernet port. This feature is particularly useful for adding Ethernet
devices to a mixed system using MDS SDx and x710 Transceivers. This
feature is different than Ethernet Bridging, which is described on Page
55 in the Bridge Configuration Section.
NOTE:
To make use of this feature, the radio must be properly autho-
rized for Ethernet data. If it is not, contact your sales represen-
tative for further information.
It is helpful to understand that IP data is terminated at the radio, yet the
payload data is transmitted OTA. As such, the radio acts as a
terminal
server
converting IP data into a serial “over-the-air port.” In other
words, a transmitting radio receives an IP message, strips off the IP
headers, and sends it over the air with VRC identification (VRC-1,
VRC-2, or VRC-3). A receiving radio may then be set up, for example,
to have
COM2
or an IP port deliver
all
VRC-1 traffic.
The radio supports Ethernet operation on
three
IP payload ports. These
settings are made on the
IP Payload Configuration Menu
(1, 2, or 3) as shown
in the screen which follows later in this section. In the Master unit only,
Multihost may need to be enabled if more than one IP Payload port is
required. Multihost feature only pertains to Packet Radio Mode.
