Technical Resources

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  Related Information

Device Certification - LonMark conformance instructions.

Design Guidelines - Technical information for developing open interoperable LonMark products.

Technical Corner - Provides answers to commonly asked technical questions.

LonMark Members who manufacture products used in Open Systems

Terminology (T - Z)

The descriptions and terminology contained within this document are made in the context of use with LonWorks® networks and products.




The destination of a connection, specified by node handle and network variable or message tag index. Each connection is defined in terms of a hub and a set of targets that connect to the hub. For network variable connections, the hub must be either the only input or the only output in the connection. For example, if the hub is an output network variable, all the targets in the connection must be input network variables.


A device comprised of a capacitor and a resistive element providing electrical termination for signals on a given channel type. Almost all networks require a specific type of terminator depending on the channel type, ex. twisted pair, and the network topology, i.e. free or bus.

Thin Client

A low-cost, centrally managed computer devoid of CD-ROM players, diskette drives, and expansion slots. The term derives from the fact that small computers in networks tend to be clients, not servers. Since the idea is to limit the capabilities of these computers to only essential applications, they tend to be purchased and remain "thin" in terms of the client applications they include.

The term "thin client" seems to be used as a synonym for both the NetPC and the network computer (NC), which are somewhat different concepts. The Net PC is based on Intel microprocessors and Windows software (Intel was a leader in defining the Net PC specification). The network computer (NC) is a concept backed by Oracle and Sun Microsystems that may or may not use Intel microprocessors and uses a Java-based operating system. The increased numbers of thin clients in today's workplace and educational facilities reflects a corporate and institutional need for low-cost computers dedicated to Internet use.


The free topology twisted pair LonWorks channel type, 78 kbps bit rate.


A bus twisted pair LonWorks channel type, 1250 kbps bit rate.


A bus twisted pair LonWorks channel type, 78 kbps bit rate.


A mechanism to group a series of service invocations into a single operation. Transactions are used to make sure that either the entire series of service invocations take effect, or that none of them do. An LNS® host application can explicitly manage transactions or it can let the NSS implicitly start and commit transactions as needed.


The device that physically connects a Neuron® Chip to its channel. The transceiver implements layer 1 of the LonTalk® protocol.  There are Network Interface Transceivers (TP-XF1250, TP-FT10), Channel Transceivers (TP-XF1250, TP-FT10) and Device Transceivers (TP-XF1250, TP-FT10, TP-XF78).

Transceiver ID

A transceiver ID is a number between 0 and 31 that represents a different type of transceiver. Transceiver IDs are reported by routers and NSIs as a function of the type of transceiver attached. Note that LonWorks routers do not support transceiver ID. For example the STDXCVR.TXT file in C:\LonWorks\types shows TP/XF-1250 with nXcvrId = 3 and TP/XF-78 with nXcvrId = 1 and the XcvrCount = 24. Also, a transceiver ID of 30 is reserved to indicate a custom transceiver. Transceiver IDs are distinct from transceiver types.

Transceiver Type

A transceiver type is a number that refers to an entry in the standard transceiver type file (C:\LonWorks\types\STDXCVR.TYP). An entry in this file may reference a transceiver ID. However, some entries may have no transceiver ID.

Typeless Network Variable

A network variable for which there is no SNVT type or length information available. Typeless network variables can be bound to any other network variable type; it is the responsibility of the installation tool's application program to prevent nonsensical connections from being formed that contain typeless network variables.

UCPT (see User Configuration Property Type)
UNVT (see User Network Variable Type)

Unconfigured Device

A device state where the device has an application image, but no network image.  The device must be configured before it can operate on the network.

Unconfiguring devices

Performed by pressing and holding the service pin down for 15-20 seconds until the power led flashes briefly (p 5-22). This is also known as decommissioning a device and can be done using the device’s Manage shortcut menu.


Data transfer from the network and the NSI toward the host.

Upstream Device

The device sending a network variable update.

User Configuration Property Type (UCPT)

A non-standard data structure used for configuration of the application program in a LonMark device. UCPTs can be used only when there is no appropriate Standard Configuration Property Type (SCPT) defined.  LonMark certified devices have UCPTs documented in resource files according to a standard format, in order to allow the devices to be configured without the need for proprietary configuration tools.

User Network Variable Type (UNVT)

A non-standard data structure used for defining the carrier for data between two-or-more devices. UNVTs can be used only when there is no appropriate Standard Network Variable Type (SNVT) defined.  LonMark certified devices have UNVTs documented in resource files according to a standard format, in order to allow the installer and end-user to interpret the data being exchanged.  The use of UNVTs for netowrk variables prevents the exchange of data between devices of different vendors unless those vendors has a pre-arranged agreement on the definition of the UNVT.  UNVTs are usually used only to display information to a head-end console or to share private (vendor-specific) data.

User Profiles

1) Can only be enabled by the Administrator of the network. The Administrator will set the following values for each user: UI setting, Access control (subsystems), Privileges (object in a subsystem) and Actions (ex. Read, Modify, Commission, etc.). This allows different users to log on to a network and only make changes according to their user name. All passwords are case sensitive and cannot be retrieved if they have been forgotten.

2) Manufacturer-defined functional profiles created to ease installation and configuration by the end user: User Functional Profile Templates (UFPTs).


For optimum performance when attached to LonWorks networks, use an LNS Fast Network Interface (also known as a VNI).


Causes the device to generate an application dependant audible or visible response such as flashing the power LED.  This command will ONLY have an effect if the device supports the Wink function.  This can be useful for identification and testing purposes.

XIF (see Device Interface File)

XML (Extensible Markup Language)

A flexible way to create standard information formats and share both the format and the data on the World Wide Web.


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