300 BPS DCM-5 Modem (260-1177) Using the DCM-5 Faxback Doc. # 5839 A modem that is connected to a computer running a Videotex software package constitutes one of the most common and (exciting!) ways to use your DCM-5. This section will describe how to use the DCM-5 with VIDTEX (the Videotex program) on Tandy computers. If you're interested in writing your own programs for the DCM-5, refer to the section of this manual entitled PROGRAMMING INFORMATION. It will give you a detailed account of how the DCM-5 works but on a technical level. "TALKING" WITH DCM-5 The DCM-5 accepts the following communications protocol. Be sure to match you computer's protocol to these settings: 300 baud 8 Data bits No Parity 1 Stop Bit MANUAL/ORIGINATE MODE The most common and probably the easiest method of calling an information service is manual/originate. In this mode, you'll have to be near the DCM-5 and computer when you are using Videotex (attended use). Once the program is loaded, you must dial the information service and begin communications. You need to change one parameter. Since you want to "talk" with the information service manually, set to manual mode. To change from automatic to manual, type M. Press L to check the current parameter settings. You will see MODE changed to M (setting the DCM-5 to manual mode). Now pick up the telephone and dial the information service phone number. When the information service answers the phone, you will hear a high-pitched tone. Press X to execute the command (manual originate mode). As soon as the DCM-5 detects this signal, it goes "on-line." The OFF HOOK indicator will light. Then the RECEIVED DATA indicator will turn on. At the same time, you will hear a low-pitched tone. Gently hang up the phone. You can then begin following the instructions detailed in your Videotex and information service user's guides. MANUAL/ANSWER MODE If you wish to use VIDTEX to communicate with another person who is also using VIDTEX and a DCM-5, one of you will have to set the DCM-5 in originate mode and the other person will have to set the DCM-5 in answer mode. It is up to you and the person you're communicating with to decide who is to be originator and who is to be answerer. When you are to be the answerer, you need to change the TYPE to answer. Type *L on your computer. When the display shows the current parameter settings, type A. When you receive a call, pick up the handset and listen for the high-pitched tone. Press X and the DCM-5 will be in the answer mode. The OFF HOOK indicator will light. Gently hang up the telephone. You can then begin communicating with the other person. AUTOMATIC MODE OPERATION Automatic mode operation allows you to leave your DCM-5 and computer unattended and the DCM-5 will automatically dial or answer the phone. This is useful for many reasons, foremost among them being that the DCM-5 automatically can dial numbers at night when the phone rates are cheaper, transfer information to another computer and then hang up the phone. The DCM-5 has both auto/originate (for dialing) and auto/answer (for answering) operations. To set the DCM-5 to automatic mode, first type *L to enter command mode. The screen will show the current parameter settings. If the MODE displayed is M, then type M to set to automatic mode. Type L to confirm that the mode is now A. Change the type setting, if required. You may have to set the DCM-5 for the number of rings for auto-answering. The ring number is set to 2 at power-on. This means your DCM-5 will seize the phone line after two rings. For auto/originate, you will have to enter the phone number. The DCM-5 will dial the call automatically one time. When you need to change the number or rings before answering, type I to bring the I command setting (page 28) to the screen. The display prompts: ANSWER ON 1-9 RINGS OR CR FOR NO CHANGE = When you do not need to change the number of rings, answer this prompt with a CR (carriage return) by pressing . If you do, type in the number. Note that only the number keys or the key is accepted. If you press any other key, the DCM-5 will "echo" the typed key (if displayable) and re-ask the question. When you've responded to the first prompt, the display shows: RETRY FOR 1-9 TIMES OR CR FOR NO CHANGE = You must answer this prompt with a CR (carriage return or ENTER key) to default to 1, or use the 1 key. The DCM-5 will not properly support dial re-tries where the re-try prompt was answered with a value greater than one. For entering the telephone number (see the dialer programming command, page 26). You can also specify the dialing method (either pulse or tone dialing), the dialing speed and any pause during dialing (which may be necessary to access an outside line in a behind PBX). For example, enter DT9P1234567 for tone dialing, 9 for access code to thee outside line, pause for 2 seconds, dialing 1234567. For more detailed information on storing a telephone number, see the next chapter, PROGRAMMING INFORMATION. When set to auto/answer mode, DO NOT pick up the receiver when your tele- phone rings! The DCM-5 will seize the telephone line after the designated number of rings. In the auto/originate mode, the DCM-5 will dial the number you programmed as soon as you type X. The stored number will be kept in memory until you turn off or re-program the DCM-5. COMMUNICATION EXAMPLES The following illustrates some of the methods you can use while in either manual or automatic and the originate or answer modes. 1. With the DCM-5 and the communications software initialized, to use the default parameter settings, type *X. When the X command is received, the DCM-5 will look for the carrier detect. If a number has not been dialed, the DCM-5 will hang up after not locating a true carrier. The manual/originate mode is useful when receiving computer files (such as programs) from a remote computer using communications software. 2. At power-up, to change the parameters to auto dial so that the telephone number 1234567 will automatically be dialed, press L for the List command. Then type the following. (NOTE: You need not enter R if your phone line is pulse type since pulse dialing is defaulted.): D1234567X 3. With the system fully initialized, to indicate fast tone dialing of above telephone number, you would type: FDT1234567X 4. To change the DCM-5 setting to answer, after disconnection, type: *AX 5. To change to originate mode and dial the telephone number in Step 3 above, type: * (turns off waiting for ring) * OX 6. After disconnected from Step 5, go to manual/answer by typing: *MA (Type X after picking up the handset.) 7. After disconnected from Step 6, go to manual/originate by typing: *O (Type X after confirming carrier (the high-pitched tone.)) 8. After disconnected from Step 7, go to auto/answer by typing: *MAX When the telephone rings, the DCM-5 will be in communications mode automatically after the designated number of rings. You can force (defaulted to CTRL T). PROGRAMMING INFORMATION The DCM-5 accepts data from a computer, converts the data into two-frequency tones and then sends the tones over telephone lines to another modem. In the similar way, the DCM-5 accepts tones from telephone lines and changes those tones into data that your computer understands. You can program the DCM-5 to auto-dial or auto-answer and change other parameters simply by using the programming commands via the keyboard of your computer. The following criteria must be met before computer-to-computer communication can occur: 1. Both computers must have the same communications protocol: Baud rate (300) Word length Parity Number of stop bits See your computer owner's manual to find out how to set communications protocol. 2. One modem must be in the ORIGinate mode and the other must be in the ANSwer mode. Usually, when you call another computer, you should be in the ORIGinate mode. If you receive a call, you should be in the ANSwer mode. SPACE DISCONNECT Your DCM-5 will drop the phone line any tome it receives a continuous RS-232C SPACE (ASCII BREAK) or null with no start and stop bits) for 3 seconds from the remote modem or for 1.5 seconds from your computer. This is called SPACE DISCONNECT and is in accordance with Bell 103J standards for short and long space disconnect. In all modes, except TEST, your DCM-5 will be disconnected from the phone lines if it receives a loss of carrier greater than 0.3 seconds. To regain control over your DCM-5 after it receives a space disconnect while in the automatic mode or manual mode, turn the POWER switch OFF. Then reset the DCM-5 program as desired. If your DCM-5 receives a space disconnect while in the automatic mode, the DCM-5 will execute a command (if you so programmed). When you use your DCM-5 in automatic mode, you don't have to dial any numbers or pick up your telephone receiver to answer a call--Your DCM-5 and your telephone--through your computer keyboard. This is another easy way to run certain communications programs such as Videotex. You can also send or receive data from another computer while you're not at your computer keyboard. Just write a BASIC or machine-language program and use the commands to program your DCM-5 to dial a number or answer the phone unattended. By programming your DCM-5 to download daily information to another computer after 12 midnight, for example, you'll save time and be able to take advantage of lower telephone rates. (smm 08/04/93)