User's Manual

Page 50
E Series Ethernet Radio – User Manual
Part I – TVIEW+ Management Suite - Programmer
• A pre-dened minimum time delay between packets
received at the port. Typically the time delay would reect the
absence of a couple of characters in the data stream at the
specied user port baud rate.
• Limiting the maximum number of characters which can be
put in the data frame sent over the radio channel.
• Receipt of a selected end of message (EOM) character at
the port. An ASCII carriage return (character 13) is often
used for this purpose.
As each data frame to be transmitted over the radio channel
has overhead data consisting of checksums and SID codes.
The system designer must determine the best compromise
between the ratio of overhead versus user data which
depends on packet size and user data packet transmission
latency.
SLIP / DIAGNOSTICS
SLIP is a well known protocol for transferring binary data
packets over a data link. Each data packet is delineated by
<FEND> characters, and a substitution mechanism exists
that allows these characters to be included in the data
packet. Appendix B describes the SLIP protocol which is
used extensively in UNIX™ based systems, and is closely
associated with TCP/IP networks.
The elds which can be congured are:
• Character Input timer: Set the input timer value in ms or
enter zero to disable. Range 0 - 255.
• Maximum Frame Size: Set the maximum number of
characters or enter zero to disable. Range 0 - 4095.
• Minimum Frame Size: Set the maximum number of
characters or enter zero to disable. Range 1 - 255. Only
available when AES Encryption is on.
• EOM Character: Select the check box to the left of the
description to enable and enter the EOM character as a
decimal value. Range 0 - 255.
• LIVE Framing: Select the check box to the left of the
description to enable live framing mode.
Note : When AES encryption has been turned ON, the packet layer
is modied to suit the xed format requirements of AES encryption.
This may result in changes to the data latency and throughput in
some modes.
The diagnostics controller package uses the SLIP protocol to
communicate between base station and remote modems.
DNP-3 / IEC870
This selection congures the PAD driver to implement the
DNP-3 Protocol and IEC870 Protocol.
Pull Down Menu Selection
The PAD driver can be congured for a number of vendor
specic protocols by selecting the desired option.
Custom Format
This selection permits PAD driver to be congured in a variety
of ways and requires a greater understanding of the system
design.
For the modem to successfully transmit its packets (or
frames) of data over the radio channel, it must be told on
what basis to delineate data packets received at the data
port. Once the end of a data packet has been received at the
port the data frame is closed and transmission over the radio
channel commences. Delineation of data packets can be
congured to occur via any combination of:
Modbus
This selection congures the PAD driver with options
automatically set to implement the MODBUS protocol, e.g. 5
mSec timer.
Custom
Other congurations of the PAD driver can be selected via
the Custom button which displays a dialogue box to permit
selection of several conguration options as follows: