Sierra Wireless DART 300 Modem User Manual


 
Feature Reference DART 300 Modem
Page 40 2110212 Rev 1.0
other callers are dropped. If the calling client closes its session and then dials a new session, it
will likely use a different port number and thus appear as a new (different) client call.
If the value is non-zero, the modem will accept packets from other clients but buffer them based
on the locking time (from 0.1s to 25.5s) set in the register.
The modem will queue client packets, expecting the local host to respond to each client in turn.
As each response is sent, or the timer expires, the next client in the queue is allocated the session.
The client’s packets are delivered to the local host, up to (but not including) a packet from a
different client. A new lock is set and the timer restarts.
Packets are delivered in the order they are received. If more than one packet arrives from a given
client, those packets that arrive without intervening ones from another source will be delivered to
the host as a set. Only one response is needed to clear the lock and allow the next client’s
packet(s) through.
If packets arrive from the currently active client while the local host has not replied, and the
modem has not received packets from other clients, then the packets will be delivered to the local
host immediately. These are packets from the currently active client. Buffering of packets begins
with the first packet from a client other than the active one. From that point, all packets from any
client (including the active one) are placed in the queue on a first-in first-out (FIFO) basis,
pending release of the lock.
Implementation
To use a UDP Server configuration without a server lock (AT is omitted for brevity):
1. +WS45=0 to set UDP mode
2. Optionally set the Friends List as described in Section 5.1.
3. +WS217=0 to disable the Server Receive Lock.
4. +WS212=n where n is the port number (from 1025 to 4999) the modem will listen to for
client session requests. The default is port 2100.
5. S0=1 to set auto-answer (or S0=0 for manual answer).
6. &W to save the configuration.
Provided the modem is registered on the CDPD network, it is now ready to receive client requests
for unique client/server sessions.
To use a UDP Server configuration with a server lock:
1. +WS45=0 to set UDP mode
2. Optionally set the Friends List as described in Section 5.1.
3. +WS217=n where n is the duration (in tenths of a second) to allow the host to respond to a
client before giving the session to the next caller.
4. +WS212=n where n is the port number (from 1025 to 4999) the modem will listen to for
client session requests. The default is port 2100.
5. S0=1 to set auto-answer (or S0=0 for manual answer).
6. &W to save the configuration.
Provided the modem is registered on the CDPD network, it is now ready to open a server session
for multiple clients on a first-come first-served basis.
6.2.1.3. Disabling the UDP Server
It is possible to completely disable the UDP server so that no client requests will ever be accepted.
This prevents the RI signal and RING message from occurring. The modem will only be able to
act as a client. The modem will actually respond to client requests with an indication that there is
no server available.
To disable the server side entirely, set the listening port to zero: +WS212=0.