The purposes of the research were (1) to study CAT Telecom Public Company Limited (CAT) staffs perception of organizational communication (2) to study CAT staffs’ efficiency of organizational communication (3) to study the comparison of the differences on personal aspect and efficiency of organizational communication (4) to study perception of organizational communication related to efficiency of organizational communication. The sample group was 380 samples who were CAT staffs all over the country. The questionnaires were distributed to the selected respondents in order to collect data. The statistical methods used to analyze data were frequency percentage mean standard deviation t-test One-way analysis of variance and Pearson product moment correlation coefficient. The results indicated the majority of female respondents for 60.26 percent. The bachelor’s degree or equivalence comprised 48.95 percent. There were experience group from 6-10 years was 28.68 percent and 70.26 percent of work in central location. The CAT staffs’ perception of organizational communication was in high level (xˉ=3.79). Considering each aspect found that all aspect were in high level included receiving message aspect (xˉ=3.80) interesting in message (xˉ=3.63) ability to remember the message (xˉ=3.71) and credibility of message (xˉ=3.99). The overview of efficiency of organizational communication of CAT was in high level (xˉ=3.70). Considering each aspect found that all aspect were in high level included sender (xˉ=3.72) message (xˉ=3.72) channel (xˉ=3.64) and receiver (xˉ=3.74). The result of the hypothesis found that: Personal aspect was the difference on education experience and work location had different efficiency of organizational communication with statistical significance at level .05 while different gender showed no differences of the efficiency of organizational communication. The perception of organizational communication was unrelated to the efficiency of organizational communication. xˉ=3.72) message (xˉ=3.72) channel (xˉ=3.64) and receiver (xˉ=3.74).

The purpose of this descriptive study is to behaviors perceived communication effectiveness and the relationship between communication behaviors and perceived intra-organizational communication effectiveness using 70 sets of closed-end questionnaires as a tool for data collection from employees at a selected independent organization. Statistical methods for data analysis included percentage mean( μ ) standard deviation( σ) and correlation coefficient. The results of the study indicate that most of the survey respondents ae male aged 51 years and older with a marital status. The education level is bachelor’s degree. In respect of information perception intra-organization matters are the main priority among employees with a focus on the information within the organizational unit they belong to or benefits related to them. With regard to communication frequency and channels internal email is mainly used followed by Facebook and Line respectively due to restricted access to communication tools at work. On aspect of intra-organizational communication efficiency straight-to-the-point communication speed and perception are found mainly with the matters within the organization or the work unit the employees belong to. When considering the credibility of the information the emphasis is placed on the content of the order coming from within the organization substantially affecting the communication efficiency. Thus there is the close relationship between information perception and intra-organizational communication efficiency as the correlation is significant at 0.05 level. It can be said that employees at this organization pay considerable attention to the information within organization.