ANSI SCTE 165-11-2019 pdf free download – IPCablecom 1.5 Part 11: Analog Trunking for PBX Specification.
5 oVERVIEw
This specification describes the fiunctional requirements for an embedded client to support one-way incoming,one-way outgoing, and two-way PBX trunks. The physical interfaces used to support these trunk types are also defined.
5.1 Functional Responsibility
To maintain compliance with the IPCablecom NCS specification [NCS], the Call Agent will remain responsible forall higher order functionality whenever possible. Only when timing is critical will the endpoint be responsible forthe required functionality.For example, the endpoint is expected to out-pulse a string of successive digits whenrequested by the Call Agent. In this case, the endpoint is responsible for the timing of the duration of each digit andthe delay between them.
The endpoint is also responsible for all timing requirements related to the start method in use = wink, delay orimmediate. In fact, the start method used by the interface is transparcnt to the Call Agent.
5.2 Physical Endpoint lnterface
Various physical interfaces provided by an endpoint of an MTA are used to support the following PBX trunks:. Onc-way incoming trunk – supports calls originating from the network towards the PBX via thc MTA.A
specific example of a one-way incoming trunk is a DID PBX trunk which MUST be provided using a DID PBXphysical interface.
One-way outgoing trunk – supports calls originating on the PBX towards the network via the MTA. A specificexample of a one-way outgoing trunk is a DOD PBX trunk which MAY be provided over a number of physicalinter faces.
Two-way trunk – supports calls originating and terminating on the PBX via the MTA. A four-wireE&Mphysical interface is typically used to support two-way PBX trunks; however , other interfaces MAY also beused.
The following sections describe cach physical interface that may be provided on an MTA to support onc or more ofthe above defined PBX trunks.
5.2.1 Loop-Start Line Interface
The NCS Line package defined in the IPCablecom NCS specification [NCS] is used to support loop-start lines.Loop-start lincs are typically used for residential voice services, but MAY be used to support analog trunking forPBX.
5.2.2Ground-Start Line lnterface
Ground-start signaling interfaces are used to provide two-way service to customer-installation switching systems,e.g., legacy PBX systems.
According to [ANSI 401] ground-start signaling for two-way dial facilities was introduced to reduce the likelihoodof seizure of the line at both ends during the silent interval of the alerting signal. Giround-start signaling is typicallyused on one-way or two-way seizure PBX lines with Direct Outward Dialing (DOD) and attendant-handled
incoming call service. Ground-start lines are also used for automatically originated data servicc. The two-wircground-start line conductors transmit common-battery loop supervision, loop dial pulses or DTMF address signals,alerting signals, and voice-band signals. Ground-start lines are often used rather than loop-start lines for the following reasons:
To avoid simultancous seizurc, i.e.. glare conditions.
To allow the application of a de voltage between tip and ring and the closure of a path from the tip conductor toground as a start dial signal.
To provide a positive indication of network disconnect.
See [ANSI 401] for the network interface requirements for ground-start access lines.
5.2.3 DID PBX Trunk Interface
A one-way Direct Inward Dialing (DID) trunk interface as described in [TIA] is required to support a DID interface of a PBX. DID trunks can only make calls in the direction from the network towards the PBX.ANSI SCTE 165-11 pdf download.