
User’s Guide | Local DTE/DCE Interface |
CAUTION
Due to
Details
UPD and TCP sessions use the D (Dial) command to open a client session. Server sessions are opened when the modem
If Quiet is enabled (Q1) then the local host should allow the 500ms delay from the assertion of DCD before beginning transmissions. For server sessions using Quiet, there are no messages from the modem’s command processor; therefore all traffic from the modem can be considered data.
SLIP/PPP connections issue either D (Dial) or O
If the host has escaped from data state and kept the modem in
4.1.5.2.Data to Command State
When the modem changes to command state, there will be an OK result issued. This may be preceded by another result (such as NO CARRIER) to indicate that the session was closed by an event outside the modem. A closed session requires the modem to return to command state.
NOTE
A transition to command state from data state does not require that the session be closed. This means that DCD will remain asserted while the modem is in command state,
Details
Several events can cause the modem to transition from data to command state based on mode. UDP and TCP PAD mode transitions:
•The modem receives the Time Dependent Escape Sequence (TDES) (Section 6.6.3.1)
•The modem receives the Time Independent Escape Sequence (TIES) (Section 6.6.3.2)
•DTR is
•The UDP or TCP PAD Session Timeout (S30) expires due to inactivity on the connection.
•The remote terminal closes the session (TCP closing handshake).
•The modem is reset or
SLIP mode transitions:
•DTR is
•The modem receives the escape sequence as a SLIP frame (0xC0 +++ 0xC0)
•The modem is reset or
2110212 Rev 1.0 | Page 19 |