At a Glance:
- Switching on LB lines
- Renewal of ring power pulses in LB lines
The USE2.OB interface attachment converts the digit codes used in the system into allocated LB call signals and vice versa.
Voice monitoring can be set in this model. When the option for voice monitoring is set, after a pause in conversation of 60 seconds, the conversation connection is terminated.
The area of use for the USE2.OB attachment is train stations, stops or routes which are not occupied by a traffic superintendent anymore and at which a sig-nalling system is not required. The digital exchange system DVS-21 with USE2.OB interface transfers connections to occupied electronic control signal boxes or to control centres.
Application example LB line forwarding
Using the USE2.OB interface the DVS-21 can forward calls originating from a local battery telephone (LB telephone). One USE2.OB attachment is required per LB device (LB line in 2-wire technology). Incoming and outgoing calls can be transferred over multiple DVS-21 systems using E1 connections (4FTR carrier card with E1 attachment).
One LB line in 2-wire technology can be connected per USE2.OB interface (4-wire technology only with double the number of interfaces).
The following functions are active for LB operation:
- Call recognition
- Call generation
- Voice recognition
- Codec + filter
The interaction of the individual functions is illustrated in the following block dia-gram.
Block diagram USE2.OB
The attachment, call recognition, receives the incoming dialling information. The dialling information is galvanically separated and adapted through an opto-coupler, passed to the microcontroller (control unit) and there processed.
The attachment, call generation, is switched through relay contacts over the LB line and generates the dialling pulses controlled by the processor.
The attachment, voice recognition, is used by the microcontroller to determine the presence of voice signals. Voice signals detected inside a time window cause the connection to be maintained. If there is no speech inside of the time window then the connection is terminated.
Sensitivity and time can be configured using the ICS software.
Codec + Filter
The main component of the codec/filter attachment is a programmable PCM co-dec/filter building block. Using this the sending and receiving level can be config-ured. It also suppresses the return transmission of the voice signal of the dialogue partner. This is realized through a configurable filter unit and out-of-phase over-loading of the return channel. This effectively prevents feedback.
The sending and receiving level as well as the filter values can be configured us-ing the ICS software.
The Symbols on the Front Plate and their Meaning:
|The System Blinker
Addressing from processor taking place
BUS output works as push-push operation with the system blinker
BUS input works as push-pull operation with the system blinker
Incoming call signal / voice signal recognized
Outgoing call signal
Signals an invalid LB call signal
|Operating Voltage:||+/-5 V (control)|
|Operating Voltage:||48 V (output amplifier)|
|Operational Current (48V):||35 mA|
|Operational Current (+5V):||30 mA|
|Operational Current (-5V)||12 mA|
|Temperature Range:||0 °C to 45 °C|