Appendix F: IHETS Digital TeleResponse

NOTE: The lease for the satellite system will expire June 30, 2006. IHETS will not support the system after that time and is offering a new service, IHETS Interactive, to replace it.

Description of equipment, installation, and operation of the IHETS Digital TeleResponse classroom talkback system

Digital TeleResponse (DTR) is an audio communication system used by IHETS to allow students to communicate with their professors during live classes. DTR can also be used to participate in group discussions and general classroom activities. The DTR system uses a standard ‘dial-up’ connection to a central controller for automated switching. The user presses a single button, listens to the voice prompts, and speaks to the professor, using the push-to-talk button.

The Digital TeleResponse system was designed to operate in conjunction with the IHETS satellite video network. DTR consists of three primary components: the Digital TeleResponse briefcase unit, the addressable control module, and the power supply module.

• Briefcase: The briefcase is used at the remote classroom and contains the handset that the student uses to ‘talk’ to the professor. In order to function, the briefcase must be plugged into a special control module that is normally mounted on the wall near the television. Once the briefcase is plugged into the control module, the student will press and release the button located on the side of the handset. When the green light inside the briefcase illuminates, the student will use the button on the side of the handset as a push-to-talk button to communicate with the professor.
• Addressable control module: The addressable control module (ACM) is a small unit that mounts on the wall and provides the necessary connections to operate the briefcase. When a student wants to use the system, she will simply plug the briefcase into the ACM, and connect the muting cable (if necessary).
• Power supply module: A power supply module (PSM) is a low-voltage transformer that supplies power/electricity to the DTR briefcase.

IHETS provides a basic DTR system that includes all necessary components for equipping one classroom. The system includes a briefcase, an ACM, and a plug-in transformer for electrical power. If more than one classroom is being installed, additional equipment may be purchased from IHETS.

• Requirements: The IHETS DTR system communicates with the central control system via a standard analog telephone line. This line is the responsibility of the user. It is required that a single line be installed for the dedicated use of DTR. This dedicated line must be installed in the classroom, and must terminate in a standard RJ-11 (modular) jack. The dedicated DTR line must also support touch-tone dialing.
• To facilitate the briefcase installation, IHETS will use this same telephone line to program the briefcase unit and its dialing sequence. Please note the telephone number for the installed circuit and advise IHETS engineers. If special dialing instructions are used on the dedicated DTR circuit, IHETS engineers will need to know that information in order to properly program the briefcase.
• Addressable control module: The addressable control module (ACM) is installed on the wall near the television receiver. The briefcase has a cable that plugs directly into the ACM. The ACM also connects to the analog telephone line and receives power from the low-voltage transformer.
• Receive site coordinators may have local main-tenance personnel install the ACM or an electrical contractor can be hired for this purpose. Installation of the ACM requires that a low-voltage transformer be installed near the location chosen. The transformer is a standard conduit mount and is usually left on continuously.

Next is the connection that is necessary to prevent feedback and echo. You will be using a ‘muting’ cable that has a single, quarter-inch wide plug. It connects the television to the ACM. The large end (with the black wrapping) must be inserted into the jack on the television with the other end (connector only) connected to the ACM.

• Operation: When a student wishes to ask a question or participate in a group discussion, they simply press and release the red button on the handset. Within a few seconds, the briefcase unit will automatically connect the student to the correct studio. When the green light inside the briefcase illuminates, the student can then push the handset button to talk. The student can speak normally into the handset while the button is depressed. When the handset button is released, the student will hear the answer to his question, via the television.
• If the student does not use the DTR system for an extended period of time, the briefcase unit will automatically disconnect. This auto-disconnect option is used to keep long distance charges to a minimum. If a student wishes to disconnect on his own, he can press the Help/Trouble button inside the briefcase.
• For help or to report trouble: If a student has a problem he wishes to report or is experiencing other trouble, he can press the Help/Trouble button inside the briefcase unit. After a few seconds, the briefcase unit will connect him to a special control room operator for assistance (direct dial to the control room is 317.263.8989 or 800.556.7612).

Additional information

If a receive site coordinator has additional questions, please contact the IHETS Help Desk.