DataBand E V User Manual
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© 2012 Patapsco Designs Ltd
Multicast
A packet sent from one source to many destinations. Used for delivering a separate, reliable and prioritisable
clock source by Patapsco devices.
Multiplexer
A device which takes input signals from many separate devices and places them onto a single output line,
allowing multiple single users to share one large, centralised resource. See also De-multiplexer.
MUX
See Multiplexer.
N ailed
‘Always on’. A way of describing a TDM connection where timeslots are always active between a source and
destination, as opposed to a dynamic ISDN connection, where timeslots (b-channels) are connected and
disconnected as required.
N AT
Network Address Translation. A method of changing the destination IP address of IP packets. Used in routed
network environments to access private (hidden) IP device addresses from public IP networks.
N ode
In terms of DbManager, an icon representing a single Patapsco device.
N T
Network Terminal. The interface type of a synchronous network connection. Devices which connect to the
network must do so using TE interfaces (see TE).
N udge
In terms of the Jitter Buffer – adding (extend) or deleting (reduce) a packet into/from the Jitter Buffer in order
to centre the fill-point within the buffer.
Ov erlap
When telephony calls are made by dialing single digits one after the other (as opposed to En-bloc, where all
of the numbers are dialed at the same time).
P acket Switched
N etwork
An Ethernet based network. PSN’s may support many different Ethernet-based packet protocols built on top
of Ethernet standards.
P ackets
A formatted capsule containing user data, headers and protocol descriptors. Used for IP/Ethernet
communications.
P DH
Plesiochronous/Plesiosynchronous Digital Hierarchy. A method of connecting together two synchronous
networks which use a different clock source to each other. Clocks are passed bi-directionally across the
system. This method of clocking requires the devices used to be compatible with PDH operation.
P DV
Potential Delay Variation. The difference in transmit and receive delay (latency) which packets have when
sent over a Packet Switched Network. This is usually caused by poor quality, heavily loaded networks.
Patapsco products use a configurable Jitter Buffer to counteract the effects of PDV.
P ermanent Link
An advanced setting used on ISDN BRI ports to keep layer 1 and 2 running at all times.
P hantom P ower
Liberator S can provide Phantom Power on its ISDN BRI ports to power ISDN devices which do not have their
own power sources. Power Feed runs at -40VDC.
P ing
An ICMP packet which is sent to a device to check its presence on a network. The device which receives the
Ping will reply, and the reply will be timestamped so that the latency between the two devices can be
calculated. Sometimes a device may reply to a Ping on another device’s behalf, which can confuse
diagnostics taken simply using Ping messages.
P lesiochronous/
P lesiosynchronou
s
See PDH.
P ort
An interface for connection to another device. In terms of UDP packets, a port number is the virtual port
which a packet will use when it arrives at its destination. Port numbers are assigned so that virtual ports can
be opened and closed on firewalls.
P OTS
Plain Old Telephone Service. The public telephone network. Connections are analogue, and therefore not
supported by Patapsco equipment.
P ower F eed
The same as Phantom Power.
