In an organization, communication flows in 5 main directions-
1. Downward
2. Upward
3. Lateral
4. Diagonal
5. External

1. Downward Flow of Communication: Communication that flows from a higher level in an organization to a lower level is a downward communication. In other words, communication from superiors to subordinates in a chain of command is a downward communication. This communication flow is used by the managers to transmit work-related information to the employees at lower levels. Employees require this information for performing their jobs and for meeting the expectations of their managers. Downward communication is used by the managers for the following purposes -
Providing feedback on employees performance
Giving job instructions
Providing a complete understanding of the employees job as well as to communicate them how their job is related to other jobs in the organization.
Communicating the organizations mission and vision to the employees.
Highlighting the areas of attention.

Organizational publications, circulars, letter to employees, group meetings etc are all examples of downward communication. In order to have effective and error-free downward communication, managers must:

• Specify communication objective
• Ensure that the message is accurate, specific and unambiguous.
• Utilize the best communication technique to convey the message to the receiver in right form

2. Upward Flow of Communication: Communication that flows to a higher level in an organization is called upward communication. It provides feedback on how well the organization is functioning. The subordinates use upward communication to convey their problems and performances to their superiors.

The subordinates also use upward communication to tell how well they have understood the downward communication. It can also be used by the employees to share their views and ideas and to participate in the decision-making process.
Upward communication leads to a more committed and loyal workforce in an organization because the employees are given a chance to raise and speak dissatisfaction issues to the higher levels.

The managers get to know about the employees feelings towards their jobs, peers, supervisor and organization in general. Managers can thus accordingly take actions for improving things.
Grievance Redressal System, Complaint and Suggestion Box, Job Satisfaction surveys etc all help in improving upward communication. Other examples of Upward Communication are -performance reports made by low level management for reviewing by higher level management, employee attitude surveys, letters from employees, employee-manager discussions etc.

3. Lateral / Horizontal Communication: Communication that takes place at same levels of hierarchy in an organization is called lateral communication, i.e., communication between peers, between managers at same levels or between any horizontally equivalent organizational member. The advantages of horizontal communication are as follows:
It is time saving.
It facilitates co-ordination of the task.
It facilitates co-operation among team members.
It provides emotional and social assistance to the organizational members.
It helps in solving various organizational problems.
It is a means of information sharing
It can also be used for resolving conflicts of a department with other department or conflicts within a department.

4. Diagonal Communication: Communication that takes place between a manager and employees of other workgroups is called diagonal communication. It generally does not appear on organizational chart. For instance - To design a training module a training manager interacts with an Operations personnel to enquire about the way they perform their task.

5. External Communication: Communication that takes place between a manager and external groups such as - suppliers, vendors, banks, financial institutes etc. For instance - To raise capital the Managing director would interact with the Bank Manager.