Ericsson LBI-39076B system manual Description, GTI Units

DESCRIPTION LBI-39076B

The Site Controller computer directs up to 16 levels of toll call restrictions, up to 15 rotary hunt sequences, 8 de- queuing priority levels, and inbound interconnect enable/disable assignments, for each ID number. It also accumulates interconnect call activity data for the System Manager.

The standard ELI option consists of one or more GTI units, one GTI Interface card, one set of two GTI Configurator software diskettes, one set of two Site Controller computer Personality PROMs, and the necessary cables and hardware. The ELI option may also consist of an optional Interconnect Accounting Manager (IAM) unit. The GTI interface card is to be installed into one of the GTI units making it the Master GTI.

The ELI option utilizes a distributed switching system architecture that distributes the switching function between the separate GTI units rather than concentrating it at a centrally located telephone switch. Additionally, each GTI unit receives its power from a separate repeater power supply.

A typical ELI installation containing two GTI units, a Master GTI, and an optional IAM is shown in

Figure 1. The function of each cable and bus termination shown, is as follows (see parts list for part numbers):

S - The serial data cables connect the Master GTI to the Site Controller computer. (Two are used.)

P - The power cable connects the optional IAM to the power supply of the associated repeater. (One is used if an IAM is supplied.)

A/P - The audio/power cable connects a GTI or Master GTI to a MASTR II/III repeater and its power supply. (One is used for each GTI or Master GTI assigned to a MASTR II/III repeater.)

PCM - The PCM/Data bus sections connect each GTI, the Master GTI, and the optional IAM in a daisy- chain. (Section lengths depend upon the position of the units. The total number of bus sections is one less than total number of units used.)

T - The termination for the PCM/Data bus terminates the high channel end of the bus. (One is used.)

GTI UNITS

Each GTI (Global Telephone Interconnect) unit contains both a radio channel interface and a telephone line interface. For each interface, the GTI contains both analog- to-digital and digital-to-analog converters, and a digital signal processor. The relation of these circuits to the audio paths is shown in

Figure 2.

The radio channel interface provides the following functions:

∙Decodes DTMF from radio for radio-originated call.

∙Sends ringback or busy tone to radio for radio- originated call.

∙Sends ringing signal to radio for telephone- originated call.

Repeater	CODEC	Digital
	Digital/Analog	Signal
Interface
	Converter	Processor
		Bus
		Driver
		and
		Receiver
Telephone	CODEC	Digital
	Digital/Analog	Signal
Interface
	Converter	Processor
		PCM / Data Bus

Figure 2 - GTI Audio Paths

The telephone line interface provides the following functions for telephone-originated calls:

∙Detects signaling from telephone line.

∙Applies signaling to seize telephone line.

∙Detects and decodes overdialed telephone number digits from telephone line.

∙Sends voice prompts to telephone line.

∙Detects end-of-call signaling from telephone line.

∙Removes signaling to drop telephone line.

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