Teledesign Systems Inc TS4000EH Manuel D’Utilisation

Control Description 
Slot Time 

This sets the transmit slot time (see Setting Slot Time). 

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. 
 
Type Description 
Data Packets 

These are any packets that carry user data.  These include 
data packets for all the different types of transfers (i.e. 
Individual, Individual w/o ACK, Broadcast). These values 
are set on the Packet for Port tab. 

ACK Packets 

These are the acknowledgment packets for the individually 
addressed data packets.  These values are set on the 
Packet for Port tab. 

Relay Packets 

These are any packets that repeated with the store and 
forward repeater option.  Both data packets and ACK 
packets can be repeated. 

 
Selection Description 
Packet Type 

The store and forward filtering is based on the packet type.  

For most applications the newer Address based filtering is 
simpler and more versatile.  

Address 

The store and forward filtering is based on the address of 
the source and destination units. 

This selection requires that the modem firmware is version 
5.20 or higher. 

 
Selection Description 
None 

No packets are repeated. 

Some 

The packets repeated are determined by the address list 
control (see below). 

All 

All packets are repeated.    

 
This control consists of a list of address ranges.  Each item in the list represents 
a range of addresses that are repeated.  A packet is repeated if the packet’s 
source or destination address matches an address range in the list.  The 
addresses consist of a group address and a minimum and maximum individual