use strict;
use warnings;

my $fname="file55.txt";

print "additionalInfo00,notificationType,eventType,friendlyName\n";
open my $f,"<",$fname or die "Cannot open $fname : $!";
local $/= "\n\n";

while (my $event =<$f>){
  my %info;
  my @lines = split /\n/,$event;
  for (@lines){
     chomp;
     next unless my ($k, $v)=/(\S+) = (.+)/;
     $v=~s/^\s*"//;
     $v=~s/"?\s*$//;
     $info{$k} = $v;
  }
  $info{additionalInfo00} or next;
  print "\"", 
    join('","', map {$info{$_}} qw|additionalInfo00 notificationType e
+ventType friendlyName|)
    ,"\"\n";
  
}
[download]

Output:

additionalInfo00,notificationType,eventType,friendlyName
"RMServiceState =inService","alarmRaise","communicationsAlarm","B_GSM-
+R_N0a.12_N11BSC2.01"
"RMServiceState =notInService","alarmRaise","communicationsAlarm","Tra
+il_S42.3_S42.6_01"
[download]