User`s guide

SLTA- 10 Adapter Timing Data
Certain aspects of the SLTA-10 Adapter link and transport layer protocols implement
fail-safe timeouts in order to control the time spent waiting for protocol states to
change when errors occur.
Downlink Byte-to-Byte Receive Timeout
The downlink byte-to-byte receive timeout is the maximum allowable period between
the end of a single byte data frame sent downlink to the SLTA-10 Adapter, to the end
of the next single byte data frame sent downlink to the SLTA-10 Adapter. This
period is 100ms in local host mode and 1 second in remote host mode. When this
timeout occurs, the SLTA-10 Adapter discards the downlink buffer and returns to the
NORMAL state. If the reliable transport protocol is enabled, the SLTA-10 Adapter also
sends a NACK byte after this timeout.
Up/ink Message Life
The uplink message life is the maximum allowable period between the SLTA-10
Adapter sending an ALERT byte to the host and the host responding with an ALERT
ACK byte. This period is 100ms in local host mode and 1 second in remote host
mode. When this timeout occurs, the SLTA-10 Adapter will resend the ALERT byte.
This process is repeated until 3 seconds have elapsed, after which the uplink message
is discarded. This timeout only applies to the ALERT/ACK link protocol and is not
used for the buffered link protocol.
ACK/NACK Receive Timeout
When using the reliable transport protocol, the SLTA-10 Adapter will wait for the
ACK or NACK byte to be sent downlink following the end of the uplink transmission
of a message.
This period is 1 second, after which the SLTA-10 Adapter will re-send
the uplink message.
Up/ink Timeout Message Retry Count
When using the reliable transport protocol the SLTA-10 Adapter will re-send uplink
messages whenever the AClUNACK timeout period has elapsed.
This retry process is
limited to 5 retries, after which the uplink message is discarded. There is no retry
limit applied to re-sends due to the reception of the NACK byte.
Session Layer Protocol
The network interface link and transport protocols described above are
used for all host-to-SLTA communications. Layered on top of these
protocols is a downlink buffer request protocol and an uplink flow control
protocol.
9-10
Creating an SLTA-10 MIP Mode Driver