Operation, Sample applications – Omnitron Systems Technology OmniMux 400 User Manual

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In the Star mode, the OmniMux delivers twisted pair or twinax
connectivity to the workstation while providing fiber connectivity
back to the host end. The fiber conversion at the host end can be
done using any OmniRepeater

fiber converter.

The Demux-Star mode is used for multi-drop applications, when
seven or less workstations at the far end are required. In this
configuration, the OmniMux with an OmniMux XL multi-port
mux supports the multi-drop requirement and allows a single
host port to be selected for delivery to the far end.

The OmniMux utilizes a Digital Phase Locked Architecture
(PLA). It facilitates data synchronization of data rate variations
of up to -2% to +4%. It also facilitates a high degree of noise and
crosstalk immunity. Each port is monitored and each data packet
is analyzed for validity and errors. Noisy, shorted or open ports
are automatically ignored and only valid data is processed. The
retransmitted data is repeated, regenerated and reshaped; this
ensures its reliable delivery to its destination.

The Express models operate with both the 5250 and 5250 Express
protocols. Each port provides data rates of 1 Mbps for standard
5250 and 2 Mbps for 5250 Express protocol.

The host and workstations can be connected via twinax, RJ11/45
twisted pairs or a 25-pin DB25 cable. The twisted pair polarity
control allows interface to different baluns.

Utilizing two links simultaneously provides a hot backup
connection for fault tolerance in critical applications.

The OmniMux diagnostics detect and display true port activity
and parity errors. Each port is monitored for valid frame header
patterns, a detected pattern is displayed via a per-port green
Activity LED. The data is analyzed for parity errors; a detected
error is displayed via a per-port red Error LED. These features
assist in installation and monitoring of the OmniMux operation.

The OmniMux

400 is completely software transparent and no

setup or any changes are required.

OPERATION

Inputs: The OmniMux

400 is built around a Digital Phased

Locked Architecture (PLA). It allows the independent monitoring
and processing of data signals at each individual port,
discriminating between true data and noise. A priority mechanism
increases isolation between individual ports, reducing any
crosstalk effect. The incoming Manchester encoded data is over-
sampled at a rate of 16 samples per bit cell. This sampling rate is
instrumental in the digital filtering of noise. A unique clock
extraction technology facilitates the synchronization to data, with
frequency variations of -2% to +4%.

Processing: Once the data has been recovered and synchronized,
it is processed internally for validity. The processor analyzes the
Frame Header, expecting at least 3 Sync bits followed by a Code
Violation. When a legal Frame Header is detected, the port is
“marked” active and the data is allowed to be retransmitted.

Outputs: The retransmitted data is fully regenerated and
reclocked. Lost sync bits are restored, and the data is reclocked at
a 50% duty cycle, eliminating any accumulated phase shift and
clock jitter. The regenerated signal is restored to its nominal shape
and amplitude and the pre-distortion logic compensates for
anticipated phase shift and attenuation.

Displays: Per port true data activity and parity errors are displayed
by green and red LEDs. The green activity LEDs assist in
monitoring signal strength and polarity. The red Parity Error
LEDs assist in monitoring connectivity quality, signal strength,
impedance mismatches and reflections.

Auto Link Backup: Utilizing two links simultaneously provides
link redundancy. The primary F/O link can be backed up by a
“Standby” twinax or UTP link. Switching between the primary
and secondary links is done automatically by the hardware. The
Activity LEDs report the activity of each link.

The following illustrations depict several sample applications of
the OmniMux

400:

Application 1. Standard Local Controller Extension

In this application, four AS/400 controller ports must be extended
via fiber across a campus to a second building.

The host (a) is connected to the Mux (c) using baluns and UTP
cabling (b). A fiber optic cable (d) connects to the Demux (e)
which connects each port to a UTP star that provides UTP
connectivity to each workstation (f ).

SAMPLE APPLICATIONS

AS/400

OmniStar 400

OmniMux 400

(a)

twinax
"brick"

(b) baluns and
twisted pair
wiring (UTP)

(d) fiber

(e) Demux

(c) Mux

(f) UTP to workstations

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