User`s guide

6: BSC 2780/3780 Link Configuration Options
DC 900-1340I 167
6.12 Conversational Mode Option (13)
Conversational mode allows a remote station to respond to an ETX block with a data
block, instead of responding with an ACK and waiting for line turnaround. If this
option is set to enable, conversational data responses are sent (when possible) on the
line. If this option is set to disable, conversational responses are not sent; however, the
BSC software always accepts conversational data responses received on the communica-
tion line, regardless of the setting of this option.
To set this option using the DLI configuration file, use the convMode parameter; for
example,
convMode = “no”. See Table 7–2 on page 191.
6.13 Retry Limit Option (14)
This option sets the number of times the BSC software repeats a transmission when the
correct response is not received from the remote station. If the correct response is not
received within the specified number of retries, BSC resets the data link to the idle state
(sends EOT) and returns all pending write messages to the client using the
DLI_PROT_RESP_LOCAL_ACK data acknowledgment response with the dlRead
pOptArgs.iICPStatus
field set to the DLI_ICP_ERR_RETRY_EXCEEDED error.
The retry limit applies to the following BSC transmissions:
• Initial line bid (ENQ)
• Data block transmission (STX—ETB/ETX)
• Request for response (ENQ) if there is no response
In some situations the remote computer may send a WACK (wait acknowledge)
sequence instead of the expected response (ACK0 or ACK1) to a transmitted data block.
BSC transmits an ENQ in response to the received WACK. The WACK–ENQ sequences
are not counted by BSC. Thus it is possible for the remote computer to prevent the
DLI_ICP_ERR_RETRY_EXCEEDED error by sending WACK until it is ready to send the correct
response.