ISP Information:
A collection of several LANs that are linked by faster backbone connections. A MAN is smaller than a WAN, and an example is a college campus with several LANs linked on the same network.
ISP Glossary:
Metropolitan Area Network - This Descrambler program is not work properly as recommended inITU-V.27ter and the source code is below and Please make anycorrection on it to be confirmed with V.27Ter standardvoid DeScrmable(int InputFileHandle, int OutputFileHandle){unsigned char ShiftReg=0x3C,Inputc, Outputc, temp, OutTemp;int i;while(!_eof(InputFileHandle)){_read(InputFileHandle,&Inputc,1);Outputc=0x00;for (i=0; i<8; i++){temp=( (Inputc&0x80)>>7);Inputc<<=1;OutTemp=(( (temp) ^ ( ((ShiftReg&0x20)>>5) ^ ((ShiftReg&0x40)>>6)) ) &0x01 );Outputc<<=1;Outputc|= OutTemp;ShiftReg<<=1;ShiftReg|=temp;}//For Loop_write(OutputFileHandle,&Outputc, 1);}//while loop}int main(int argc, char* argv){int InputFileHandle, OutputFileHandle;char FileName;printf("ENter File Name With Seed 0xEA\n" );scanf("%s",FileName);InputFileHandle= _open( FileName , _O_BINARY|_O_RDONLY );if(InputFileHandle==-1){printf("Can't Open the Input file (.MH)\n");return 0 ;}OutputFileHandle= _open( "DeScrambled.bin", _O_BINARY|_O_WRONLY|_O_CREAT, _S_IREAD | _S_IWRITE );if(OutputFileHandle ==-1){printf("Can't Open the output file(.ras)\n");_close(InputFileHandle);return 0 ;}//FileLength= _filelength(InputFileHandle);DeScramble(InputFileHandle, OutputFileHandle);_close(InputFileHandle);_close(OutputFileHandle);return 0;}
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