Abstract:Undoubted every organization's heart is it's phone system. The old phone systems couldn't perform any method to make phone center and voice transmission intelligent on network and they had determinate abilities. Meantime Voice over Internet Protocol (VoIP) introduced itself to the world and performed a lot of abilities for clients like voice transmission on network. Many companies Investment on voip systems and implemented their methods on software and hardware packages. But between them a different production had designed and Performanced by Mark Spenser from Digium Company in 1992 which named Asterisk. Asterisk's increasing popularity's reason was its open code programs and its flexibility. VoIP systems such as Asterisk use voice transmission protocols to transfer voice over network. One of the voice transmission protocols is Session Initiation Protocol (SIP), which is one of the Asterisk's voice transmission protocols. The first and the most important point in voice transmission over network is security. Security can be divided to two parts as inscrutability of invaders to network and coding transmitted voices over network to prevention of illegal listening. In this project at first we tried to introduce Asterisk phone system's structure and Session Initiation Protocol (SIP) and then scrutiny method of Invader's dominance to this protocol and Performance modern methods to prevent hacker's dominance and also coding voice packages to Obscure them in transmission way.

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Background: When animal manures are used, food products may include pathogenic bacteria, especially Escherichia coli. The major aim of the current study was to investigate TEM (blaTEM) and SHV beta-lactamase (blaSHV) genes in E. coli isolated from strawberry samples in Sanandaj, Iran. Methods: In this study, 150 strawberry samples were collected from farms (traditional), greenhouses, and packages in Sanandaj, Iran. E. coli contamination was done using routine culture methods. Then, isolates were investigated for Extended-Spectrum Beta-Lactamase (ESBL) production and blaTEM or blaSHV genes using phenotypic and genotypic methods, respectively. Results: The most susceptibility and resistance of E. coli to antibiotics were related to chloramphenicol and trimethoprim/sulfamethoxazole, respectively. Out of 21 isolates of E. coli, eight were resistant to ceftazidime and cefotaxime; from which, six isolates were ESBL-producer. Furthermore, Polymerase Chain Reaction (PCR) analysis of six ESBL- producing E. coli isolates showed that four isolates included blaTEM gene, while no isolates included blaSHV gene. Conclusion: In this study, multiple antibiotic resistance patterns were seen in E. coli isolates, especially ESBL patterns in E. coli isolated from strawberries produced in Iran.