Hx1-Hx2 Manual-1.4.1 - Telos

A16 | appendix 1
Tie Line- See Tie Trunk.
Tie trunk- A Trunk between two PBXs. Note, a tie line is a dedicated circuit, not a switched
circuit. See Trunk.
TR-008 - See SLC-96.
Trouble Ticket-A Telco “work order” used to track Customer Repairs within the Telco. If you
call someone “inside” the Telco’s repair department, they will need this number to proceed. It
will also be needed whenever you call to check on the status of a repair. Always ask for this
number when initiating a repair request.
Trunk- A communications path between two switching systems. Note that many trunks may
be on a single circuit (if that circuit has multiple channels). The trunks most users will deal with
are between the Telco switch and a PBX. However, a Tie Trunk can connect two PBXs. See also
Tie Trunk and Trunk Group.
Trunk Group- A number of telephone channels which are functionally related. Most common
is the Hunt Group. Other common types include Incoming Trunk Groups and Outgoing Trunk
Groups. See also Combination Trunks and Two-way DID Trunks.
Trunk Side- Central Office: The side of a central office that faces the network, between
switches. Historically many CO switches could not make trunk to trunk connections (as
opposed to tandem and long distance switches, that are always used to connect trunks together).
Hence the need to distinguish between the “line side” and the “trunk side” of the switch. See
also Line Side.
Trunk Side- PBX: The side of a PBX that connects to the Telco. Historically many PBXs could
not make trunk to trunk connections. Hence the need to distinguish between the “line side” and
the “trunk side” of the switch. Since a trunk is a switch-to-switch circuit, these circuits can be
called trunks. Beware, even though you have a PBX, the Telco may still call these “lines” (even
though your PBX considers them trunks). See also Trunk and Line Side.
Two-way DID trunk- An ISDN PRI equipped for direct inward dialing. Most PBX trunks are
related to a given phone number, either alone or as part of a hunt group. In the case of a “normal”
(i.e. analog) DID Trunk, a group of phone numbers are associated with that DID trunk
(or group of trunks) and incoming calls include the DID number, so the PBX can route that
call to the correct DID extension. These are one-way (i.e. inward only) trunks. This is exactly
how ISDN PRI functions, with the DID information coming in over the D channel. There is a
big difference between a normal DID Trunk and a Two-way DID trunk over ISDN PRI. For
one thing, ISDN PRI is digital. Another distinction is that you cannot dial out over a true DID
trunk, while you can dial out over a PRI (hence the conflicting designation “Two Way Direct
Inward Dialing Trunk”).
Two Wire – A circuit path where only a single pair of wires is used. A hybrid is used to convert
from two wire to four wire circuits. No hybrid is perfect, and those used by the phone company
can be poor. However, the hybrids in Telos Hx units are approaching perfection!
USOC – Universal Service Order Code, The Bell System Universal Service Ordering Code
(USOC) system was developed to connect customer premises equipment to the public network.
These codes, adopted in part by the FCC, Part 68, Subpart F, Section 68.502, are a series of
Registered Jack (RJ) wiring configurations for telephone jacks that remain in use today. The now
famous RJ-11 and RJ-45 came from this naming convention.
Variant- The particular protocol (i.e. National ISDN-1 or ETS 300) running on a specific
switch. Not all variants are valid for a specific switch. The switch brand and model plus the
variant defines the ISND protocol. Applies to configuring the 2101. See ISDN Protocol.