Verilink 9000 Series (34-00271) Product Manual - Manual (Page 112)

90 C HAPTER 5: U NISYS P OLL /S ELECT
Drop DTR If DCD Drops
This parameter applies to dial-up applications. When set to Y (yes), the DTR
performs an on-to-off transition for 500 milliseconds, then returns to the on state.
When this parameter is set to Y, the maximum time to ETX is set to 20 seconds.
When the TXPORT unit begins receiving a message, it starts a timer. If this timer
expires before the message is complete, the TXPORT unit throws away the
received data and continues with the next poll. This prevents a terminal from
streaming data to the unit. Normally, this timer is calculated by using the speed of
the link and the maximum buffer size. Fixing the timer at 20 seconds allows using
a dial modem with a constant-speed interface where users actually connect at
different speeds. The selections are Y (yes) and N (no).
Offline Delay Retry
This is the time, in seconds, the unit waits between attempts to poll a station that is
marked offline. The selections are 1 to 255, 30.
Message Timeout
Message timeout represents the amount of time, in milliseconds, the unit waits for
a response to a message. If this time expires before a response is received, the
message is re-transmitted. If this occurs four consecutive times, the unit discards
the message.
The values for this parameter are in 10-millisecond increments. A value that is not
a factor of 10 rounds down to the nearest 10-millisecond factor.
Example: A value of 505 rounds down to 500 milliseconds.
The selections are 0 to 655350, 500.
Maximum Select Before Poll
This value represents the consecutive number of selects sent to a device before
normal polling is resumed. This prevents a locking condition where a terminal
constantly NAKs a select because it has a message to send. The selections are 1 to
255.
Active If DSR/DCD
The DSR/DCD parameter determines what leads must be present for the port to be
active. The physical DTE/DCE setting of the port also effects how these leads are
interpreted. Table 5-2 describes how the DSR and DCD leads should be set. No
polling occurs on the port until the selected requirement is met.
Table 5-2 DSR/DCD Parameters
Setting DTE DTE
B (both) DSR and DCD must be on. DTR must be on.
S (DSR only) DSR must be on. DTR must be on.
N (none) Neither. Neither.