1200 BPS DC-2212 Modem (260-1176) Installation Faxback Doc. # 5685 Tandy's DC-2212 intelligent modem is Bell System 103/113 and 212A com- patible, connecting to the telephone lines via modular connector. The RS-232 input/output of the modem interfaces directly with the RS-232C- equipped TRS-80 computers. CONNECTING TO THE TELEPHONE Although your telephone is not used for communicating (in an automatic mode) when using the modem, the type of wall connection is important in determin- ing how the DC-2212 modem is to be connected. FOR A SINGLE-LINE CONNECTION: 1. Remove your telephone's plug from the modular wall jack and insert it in the PHONE jack on the rear of the modem. 2. Plug the modem's line cord into the modular wall jack. NOTE: For a four-prong wall connection, you will need an adapter (279-360) suitable for the older style wall connector. If you telephone is wired directly to the wall, contact the telephone com- pany to have modular connections installed. FOR A MULTI-LINE CONNECTION: The DC-2212 modem can be used with a multi-line telephone, but you may need a multi-line adapter (43-270/271), a hardware modification to the modem, or both. CONNECTING TO A POWER SOURCE Insert the AC adapter's plug into the AC POWER jack on the rear panel of the modem. Plug the adapter into an electrical wall outlet or an approved power strip. Be sure to connect the adapter to the modem before you plug the adapter into the wall outlet. Otherwise, damage to the adapter could result. IMPORTANT NOTE: Use the supplied UL-Listed adapter only. Another type of adapter could damage the modem. CONNECTING TO THE COMPUTER The DC-2212 modem uses the RS-232C standard serial interface cable to con- nect to your computer. The following table provides the cable catalog numbers and location of connection. MODEM-TO-COMPUTER CABLES AND CONNECTION POINTS Model I 26-1408 Leftside, Exp. Interface Model II 26-4403 Rear panel Model III/4 26-1408 Bottom panel Model 4P 26-1408 Rear panel Model 12/16B/16B HD 26-4403 Rear panel Model 2000 26-1408 Rear panel DT-1 26-1408 Bottom panel Before connecting the DC-2212 modem to your computer, be sure to turn off power to the modem and to the computer. 1. Plug the appropriate end of the RS-232C standard DB-25 interface cable into the RS-232C jack on the rear of the modem. 2. Plug the other end of the cable into the computer's RS-232C jack. SETTING UP THE DC-2212 MODEM When you have made the peripheral connections as outlined on page 35, CONNECTING THE MODEM, you are ready to power-up and load your communications software. When the power is freshly applied, several of the LED indicators on the modem's panel will illuminate--and remain lit, depending on the status of the computer's protocol. These six indicators show the modem's internal and external operation status. (1) HIGH SPEED. Lights when the modem is in high speed (1200 baud) communications. (2) OFF-HOOK. Lights when your modem is on-line (connected to the phone lines). (3) TERMINAL READY. Lights when the terminal is supplying DTR. (4) CARRIER DETECT. Lights when the modem receives a carrier tone or gener- ates a false carrier. (5) TRANSMIT DATA. Lights when the modem is transmitting data. (6) RECEIVE DATA. Lights when the modem is receiving data. Your DC-2212 modem permits a computer or terminal to communicate with a re- mote computer by converting that computer's electrical signals into audio tones that can be efficiently handled by the telephone system. Likewise, the audio tones that the modem receives are converted back to electrical signals that are understood by the computer. SETTING COMMUNICATIONS PARAMETERS The DC-2212 modem provides data communications in full or half duplex mode at either 0-300 bits per second (asynchronous) or 1200 bps (synchronous or asynchronous). Transmission speed is always selected by the originating modem. AUTOMATIC ORIGINATE MODE operation is a default (preset) condition upon first power-up. When opened for programming with the auto-baud-rate-detect code (WAKE UP, DC-2212!), the modem automatically synchronizes the baud rate, word length, parity, and stop-bit numbers of your computer system. When programmed for AUTOMATIC ANSWER MODE operation, the modem adapts the communications protocol of the remote computer system upon receipt of a telephone-line-ringing signal. This auto-answer feature makes it possible for data transmission to occur between a remote terminal interfaced to a modem and your computer system--without intervention from the operator. Refer to your computer owner's manual or applications software user's guide if you require instructions on setting communications parameters. OPTIONAL MODEM CONFIGURATIONS The DC-2212 modem has four internal configuration options. THESE OPTIONS MUST BE PERFORMED BY A QUALIFIED RADIO SHACK SERVICE TECHNICIAN. * Multi-line phone operation * RS-232 protocol extension * Synchronous mode operation OPTION 1. MULTI-LINE PHONE OPERATION This option allows the DC-2212 modem to be used with multi-line telephones. Internal circuitry can be configured to signal a local network that there is a MODEM on the line instead of a telephone. Unless the modem is modified internally, the local network will start flashing the BUSY indicator on the multi-line telephone when the modem seizes the line! OPTION 2. RS-232 PROTOCOL EXTENSION There are two RS-232C lines that may be enabled to supply your computer with further information. These are RI and HS lines. The DC-2212 has the option of signaling the RS-232 cable that the telephone is ringing. The RI pin on the RS-232 cable will toggle at the ringing rate anytime the modem is connected to a ringing line. The HS pin on the RS-232 may be enabled to supply the terminal (computer) with high speed indication if the modem switches to 1200 baud mode upon on-line condition. OPTION 3. SYNCHRONOUS MODE OPERATION This option allows you to communicate in synchronous mode. In this mode, all automatic features are disabled and only manual operation is allowed. A jumper is used to determine if you will be required to use INT CLOCKing. (dtc-08/04/93)