User`s guide

updates are addressed to the SLTA-10 Adapter. Alternatively, another node on the
local network can command the SLTA-10 Adapter to initiate the connection.
In MIP mode, the SLTA-10 Adapter cannot itself initiate any connection; it must be
commanded to do so by another node on the local network, or else by the modem’s
detection of an incoming call.
This means, for example, another node on the local
network must initiate the dialing procedure when an alarm is detected that needs to
be reported to the host. Once a connection has been established, however, any node
on the local network can communicate with the host by addressing messages to the
SLTA-10 Adapter.
In order to support the modem functions, the SLTA-10 Adapter Switch2/CFG2 input
must be set to the Remote Host state (UP position). Switchl/CFG3 should be set to
the default ALERT/ACK link protocol (DOWN position). This automatically enables
the reliable network interface transport protocol. See Chapter 4 for details of the
configuration inputs. See Chapter 7 for using the SLTALink Manager with the
SLTA-10 NSI mode or Chapter 8 for SLTA-10 MIP mode DOS network driver
options.
Note that the packet throughput of the SLTA-10 Adapter is substantially reduced
when using a modem because of the overhead associated with modem support.
SLTA- 10 Adapter Connection States
When the SLTA-10 Adapter is operating in the remote host mode, several internal
states (or connection states) will control its behavior:
l The IDLE state is entered after power-up reset. In this state any uplink bound
messages are ignored since the SLTA-10 Adapter is not connected to a host.
The IDLE state is also entered whenever the telephone connection is broken
and the modem drops the DCD (Data Carrier Detect) line.
l The CALL-IN-PROCESS state is entered once a connection is initiated by a node
on the network connected to the SLTA-10 Adapter.
In this state uplink traffic
is still discarded while the SLTA-10 Adapter monitors the modem for
connection completion or connection failed events to occur.
l The CONNECTED state is entered once the connection is complete. The normal
network interface protocol resumes between the SLTA-10 Adapter and the
remote host. This state may be entered as a result of a node on the local
network initiating a call, or as a result of a remote host calling up this SLTA-10
Adapter.
l The FAILED state is entered if the connection process failed. This state is
operationally the same as IDLE.
The connection state of the SLTA-10 Adapter is preserved across software resets,
allowing normal network management resets to occur without breaking the
connection. The SLTA-10 Adapter will not preserve the connection state after it has
been through a power reset.
SLTA-10 Adapter User’s Guide 1 l-3