A simple low-tech solution is the use of paper and pen to write down the messages to be exchanged. Inter-office e-mail is another form of communicating through written messages. Communication using a computer involves two individuals typing their conversation and viewing it on the monitor. This can occur in an immediate mode, where conversation occurs in real time or as a series of e-mail messages where there are longer delays between sending and receiving messages. The worker who is hard of hearing may wear an assistive listening device to amplify the conversation. An interpreter may be used to facilitate conversation between two or more individuals by signing the spoken messages and voicing the signed responses. Coworkers may choose to learn some basic sign language in order to communicate with the worker who is deaf. Communication boards allow the users to point to letters or symbols to communicate ideas. The use of two TTYs that are connected to each other without an intermediate phone line can also be used to facilitate communication.