11 - ericssonhistory.com
11 - ericssonhistory.com
11 - ericssonhistory.com
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The procedure for calling, transmission of proceed-to-select signal GA,<br />
tariff zone (T), class (K) and tariff information (Z) has been described above.<br />
After receipt of B-number information from TxA the connection is set up<br />
through the transit centre {AKM) to a repeater on the route concerned. The<br />
signals for calling transit centre no. 2, call-confirmation and proceed-to-select<br />
signals are Type B. Digit transmission between the registers is done with teleprinter<br />
signals and the digits are preceded by the A subscriber's class signal.<br />
All five digits arc transmitted.<br />
The procedure is repeated through transit exchange no. 2. But only the last<br />
three digits, preceded by the class, are transmitted to the terminal exchange<br />
code receiver. The signalling on an in<strong>com</strong>ing subscriber line has been described<br />
earlier. Finally it may be mentioned that the signalling diagram shows<br />
clearing by the A subscriber, which is the normal practice.<br />
Signalling for Outgoing Semiautomatic<br />
International Traffic<br />
The signalling diagram in fig. 12 shows the signalling on the chain of circuits<br />
TxA-AERB-ARM-international exchange in another country for semiautomatic<br />
international traffic.<br />
Fig. 12<br />
Type B signalling on the chain of circuits A<br />
subscriber — terminal exchange ARB-transit<br />
centre ARM — international centre in an other<br />
country for semiautomatic international call<br />
from the A subscriber<br />
TxA A-subscriber's teleprinter and control unit<br />
Subscriber's line, single current<br />
Trunk circuit between ARB and ARM exchanges<br />
International circuit<br />
A-subscriber's tariff zone<br />
A-subscriber's category<br />
Proceed-to-select signal<br />
Access code for semiautomatic traffic<br />
Wait signal<br />
Exchange and operator identity signal and<br />
answer-back trip signal<br />
A-subscriber's answer-back with his number<br />
Proceed-to-select signal<br />
International number containing destination<br />
code, B subscriber's national number and +,<br />
which indicates end of selection<br />
8 Dial transmission of B subscriber's national<br />
number<br />
9 Answer-back trip signal<br />
10 B subscriber's answer-back<br />
15
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