
Feature Reference | DART 300 Modem |
4.1.2.States
The modem’s state, in conjunction with its condition, will govern how the modem handles traffic to and from the host and to and from a remote modem.
The modem supports two states:
•Command – the modem exchanges data with its host (DTE) as AT commands and replies.
•Data – communication is passed between the local and remote terminals as telemetry data.
4.1.3.Conditions
In addition to mode and state the modem can be in one of two conditions:
•
•
While in
In the
•In data state which passes data through the modem between the local host (DTE) and the remote terminal or network.
•In command state which exchanges data between the local host (DTE) and the modem (DCE) without passing it through the active connection to the network.
The modem must be in the
4.1.4.Sessions
In UDP and TCP PAD modes a session is open when there is an established “call” between the modem and a client or server on the network (although UDP does not guarantee the other end is
The concept of a session in SLIP and PPP modes is distinct from that in UDP and TCP PAD modes. From the DART 300 point of view, there is a SLIP or PPP session between the local host and the modem, which does not extend across the CDPD network to remote clients or servers. To the local host, there is a SLIP session with the modem and multiple client / server sessions with remote terminals.
In all modes, when there is an open session, the modem is in
4.1.5.Transition Between States
On
4.1.5.1.Command to Data State
The modem changes to data state when a session is opened either by dialling a client session or answering a server session. When a session opens, the modem issues the CONNECT message and asserts the DCD control signal.
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