User's Manual

TS4000 Radio Modem User’s Manual AirNet Packet Protocol 39
Control Description
Provide Address
at Receiver
When this control is activated, the source address of each
received packet is sent as a prefix status string to the data
(see Control and Status Strings).
Provide Positive
Transmit ACKs
When this control is activated, a status string is sent to the
user when an acknowledgment is received for a packet.
The corresponding packet number of the packet will be
provided as part of the status string (see Control and Status
Strings). This does not apply to any type of broadcast
transfer or individual transfers without acknowledgment.
Provide Negative
Transmit ACKs
When this control is activated, a status string is sent to the
user when the transfer of a packet is unsuccessful (all
retries have been sent and no acknowledgment has been
received). The corresponding packet number of the packet
will be provided as part of the status string (see Control and
Status Strings). This does not apply to any type of
broadcast transfer or individual transfers without
acknowledgment.
Provide RSSI at
Receiver
When this control is activated, the RSSI (Receive Signal
Strength Indication) of the received packet is sent as a
prefix string to the data.
The string is made up of ASCII characters as follows:
+TSRxxx
where xxx = receive signal level in –dBms
(i.e. +TSR087 = a –87dBm signal level)
Note that because the value is in –dBms (negative dBms) a
larger receive signal is represented with a smaller 3 digit
number.
For serial port 1 this control is on the Serial Port 1 Tab.
Control Description
Min Idle Slots This sets the minimum number of idle slots before a
modem attempts transmission (see Setting Min Idle Slots).
If the minimum number of idle slots is set to zero the
modem randomizes its transmission attempts with the first
slot after the channel becomes idle. For values greater
than zero, the modem waits that many slots before
randomizing its transmission attempts.
Tx Index The transmission index (TI) is the inverse of the probability
of transmitting in an idle slot. An index of 4 corresponds to
a 1/4 or 25% chance of transmitting in an idle slot. The
goal of setting TI is to maximize efficiency on the channel.
If TI is set too low then transmissions collide too often. If TI
is set too high then there is excessive unused channel time
in the system (see Setting Transmission Index).
Min Idle Slots and Tx Index can be set differently for different types of packets.
The following table describes the different packet types.
Packet Status Data
CSMA MAC Setup