Universal Serial Port Cable Interfaces; Physical" And "Logical" Devices - Alcatel Omni Switch/Router User Manual

Universal Serial Port Cable Interfaces

Universal Serial Port Cable Interfaces
The automatically senses the cable type that you plug into one of its universal serial
WSX
ports. It can sense whether the cable type is
ing interfaces:
• RS-232
• RS-449
• RS-530
• V.35
• X.21 (European)
All cable types, except
232 cable is not compatible with speeds greater than 64 Kbps. Each cable type is illustrated
and described in Appendix D, "Custom Cables."
The serial port is normally considered a physical
WSX
a physical
DCE
whether a
DCE
DTE/DCE Type and Transmit/Receive Pins
The RS-232 protocol, which is employed at the physical level for all cable types, always
defines Transmit and Receive pins in relation to the
( or ) determines the direction of data flow on your connector's Transmit and Receive
DCE DTE
pins.
If the serial port is a physical
WSX
then data is received on Receive pins and transmitted on Transmit pins. If you are using a
port as a physical
WSX
Transmit pins.

"Physical" and "Logical" Devices

This chapter refers to "physical" and "logical"
Communication Equipment) devices. A physical device operates on the network layer, and is
normally an actual piece of hardware, such as a
further be differentiated as
hardware, such as a
cal device is a conduit for data traffic but not a controller of data traffic. A physical
DTE
device is hardware, such as a
Normally physical
Logical devices operate on the Frame Relay protocol layer, and are sometimes referred to as
"Frame Relay logical" devices. Logical devices can also be broken down into
devices. Logical
Relay network and the various congestion and control parameters that govern it. Logical
devices do not control such actions as bringing up and tearing down virtual circuits; they act
upon updates and commands generated by the Frame Relay network. Logical
such as a Frame Relay switch, have a large span of control over Frame Relay network traffic.
They bring up and tear down virtual circuits, set congestion control bits in packets, and
communicate status to logical
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, are capable of access rates from 9.6 Kbps to 2 Mbps. The RS-
RS-232
device simply by plugging in a
or cable is connected.
DTE
, which is probably the most common configuration,
DTE
, then data is transmitted on the Receive pins and received on the
DCE
and
DTE DCE
, that does not control the access rate for virtual circuits. The physi-
WSX
, that does control access rates of Frame Relay traffic.
CSU/DSU
and devices are directly connected to one another.
DTE DCE
devices, again like the
DTE
devices.
DTE
or and whether it is one of the follow-
DCE DTE
device. It is possible to turn it into
DTE
cable. The
DCE WSX
. So, the type of cable you attach
DTE
(Data Terminal Equipment) and
DTE
or . Physical devices may
WSX CSU/DSU
devices. A physical
DTE
, do not have direct control over the Frame
WSX
board internally senses
(Data
DCE
device would be a piece of
DCE
and
DTE DCE
DTE
devices,
DCE