
REFERENCES
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Case 4 – STAR Modem™ in Stand Alone Mode as Server (for an intelligent
printer)
Figure 4 – Stand Alone Mode with STAR Modem™ 2 Server
The two STAR Modems™ in this case can be configured in Stand Alone Mode,
however this limits one to be the dedicated Client and the other to be the dedicated
Server. Bi-directional communication is not possible in Stand Alone modes.
Assuming that Host 1 is Client we can analyze the following transmission parameters
from both STAR Modem™ 1 and STAR Modem™ 2’s point of view :
Modem
1
Client
Transmission Mode = 2 way
ACK/NACK from Remote Host = enabled
FIFO = enabled
Handshaking = any
The Client, (Host 1) sends a message to the Remote Host (Printer) and expects
an answer from the Printer. If the answer doesn’t arrive before Radio Protocol
Timeout, Modem 1 sends NACK to the Local Host.
•
If Modem 2
Server
ACK/NACK Protocol = enabled as ACK/NACK
When
STAR Modem™ 2 receives a new message, it sends it to the Printer.
The Printer answers with ACK. If Modem 2 acknowledges within the Radio
Protocol Timeout, Modem 1 sends an Empty Answer to its Local Host (Host 1),
otherwise it sends NACK.
•
If Modem 2
Server
ACK/NACK Protocol = enabled as DATA/NACK
When
STAR Modem™ 2 receives a new message, it sends it to the Printer.
The Printer answers with DATA (a string of up to 238 characters). If Modem 2
sends this DATA answer within the Radio Protocol Timeout, Modem 1 sends it to
its local Host (Host 1), otherwise Modem 1 sends NACK.
HOST 1
Printer
Modem 1
Modem 2
Client
Server