Cabletron Systems MMAC-Plus 9F116-01, Руководство пользователя, Страница: 180 / 420

9-6 FRX/FRM 3. 3 User G uide, Rev 04
If an RS-232 DCE port is directly connected to the DTE via the
standard Cabletron cable, the maximum supported speed is 64K. If
longer cabling is used, the maximum speed is 19.2K. (The EIA
standard for RS-232 addresses speeds up to 19.2 Kbps.)
Retransmission Period
is the length of time before the node will transmit an I-frame if the previous trans-
mission is not acknowledged. If the period expires, the timer will be reset and a super-
visory frame will be transmitted demanding immediate acknowledgement. The
Maximum Retransmissions
(see that entry) counter will also be incremented.
The default value of
2000 ms
allows avoidance of unnecessary retransmission of
frames that have merely been delayed.
Maximum Retransmissions
is the maximum number of times the node will attempt to send an I-frame after a
Retransmission Period
expiration. A larger value for this parameter increases the prob-
ability of an eventual successful transmission, but a smaller value permits faster
detection of a permanent error condition.
Maximum Bytes per Frame
is the maximum frame size that will be transmitted on the port.
Generate Clock
specifies whether the port will generate the clock necessary to synchronize traffic over
the link. If the port is a physical DCE (determined by the port's I/O cable interface),
set this parameter to
Y
, since the physical DCE generates clock. If the port is DTE, set
the parameter to
N
.
Rcv Clock (TT) from DTE
allows the clock to be looped back from the DTE using the TT (Terminal Timing)
signal, which can be helpful on high-speed lines. Generally, if the local interface is
physical DCE and the line speed is above 256 Kbps, this parameter should be set to
Y
.
(Make sure the remote DTE is configured to provide the terminal timing.)
Activate Connection w/o poll
will (if enabled) activate the TPAD connection without a poll of the connected device.
Answer Non-Configured
will (if
Y
) allow the HPAD to respond to all devices on the line. If
N
, the HPAD will
respond only to those devices that are configured on the node.
On-Line System Memory Changes/Database Display
determines which set of values will change, as described under "Database and System
Memory Values" on page 5-4.
EBCDIC
stands for "Extended Binary Coded Decimal Interchange Code." Setting
EBCDIC
to
Y
requires that all devices on a line use the same character set for successive session
polls. It is activated after a session is over; i.e., an
EOT
(End of Transmission) is suc-
cessfully transmitted down the line. On expiry, a
General Poll
is transmitted, except
under certain special conditions. The timer is deactivated at
Link Down
.