SLTA-10 Adapter User’s Guide 72
Switch2/CFG2 input in the
Remote Host
setting (UP position). When
connected, the selected SLTA-10 Adapter and Host network interface link
protocol is in effect. When disconnected the only allowable link layer traffic is
of the ‘modem direct’ type, where ASCII strings are being exchanged between
the host and the modem, for example, AT commands to dial out. Any other
network interface traffic is not allowed when disconnected from the SLTA-10
Adapter. Calls to the read function will result in no network interface data
messages (
LDV_NO_MSG_AVAIL
), and any call to a write function that needs to
communicate with the SLTA-10 Adapter via the modems will result in a No
Output Buffers Available error (
LDV_NO_BUFF_AVAIL
). Once the connection is
made, normal network interface traffic may resume.
This option also enables the reliable transport protocol. This protocol includes
the addition of a message sequence number and the end of message
ACK/NACK code. See Chapter 4 for a description of this protocol.
/N
Disables the ALERT/ACK network interface link protocol, and enables the
buffered network interface link protocol. Network interface messages are sent
without waiting for the ALERT ACK response. Both sides of the interface (the
SLTA-10 Adapter and the driver) must have the same setting. This option
should not be used with the
/M
option.
/Q
Allows modem responses to be sent uplink to the host. When the telephone
link is disconnected, these messages are ASCII strings with the network
interface command type
niDRIVER
(0xF0). If
/Q
is specified, the host
application must be able to handle messages, such as
NO CARRIER
, that might
come from the modem itself if problems occur in the connection.
/X
Disables the buffer request protocol. When this option is enabled, the driver
requests the buffer count from the SLTA-10 Adapter using the
niSBUFC
(
0xE7
)
command whenever the interface is opened, or when the interface is reset, and
reports an niRESET to the host. The driver keeps track of the number of
available output buffers in the SLTA-10 Adapter by examining both uplink and
downlink messages. This option prevents the use of one message type: A local
network management command not using a request/response service.
Normally this type of message is not used. One exception could be the
Set
Node Mode: Reset
command, which would result in the node resetting and
the buffer management recovering on its own anyway. Otherwise, if this type
of message is used, no uplink response would occur and the driver could not
track the fact that a new output buffer has been made available.
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