Contents:
Transmitting Data and Faxes >
USRobotics 56K PC Card Modem User Guide
Your modem allows you to send and receive both data and fax files using your communications software. Your modem can also be used for data communications with an online service, the Internet, an electronic bulletin board system (BBS), or another modem.
Your modem supports both Class 1 and Class 2.0 faxing. The default is Class 1. If problems arise when you attempt to fax, we suggest you try changing the fax Class.
Software Settings
Transmitting Data
Transmitting Faxes
Software Settings
In your communications software, wherever you have an option, select the following settings:
- Highest transmission speed or baud rate listed
- Fax Class 1
- NONE for parity
- Word length of 8
- Stop bits set to 1
- RTS/CTS (hardware) flow control
In the modem setup section of your communications software, select your
modem model. If the correct modem does not appear on the list, use this
string to initialize your modem:
AT&FE1V1&D2&C1S0=0
Check the USRobotics Web site at www.usr.com for updated initialization strings.
Transmitting Data
Terminal Emulation Protocols
Various computer systems use different types of terminal emulation, such as IBM 3270, TTY, DEC, or ANSI. Contact the system operator of the host modem you are dialing into to determine the type of emulation to use for that connection. If the system operator is unknown, try using the ANSI terminal emulation protocol.
File Transfer Protocols
File transfer is the ability to transport files between two computers using two modems. The modems must use a file transfer protocol, which can correct errors in transmission and begin the file transfer process. Both modems must use the same file transfer protocol.
At the time you set up a file transfer, your communications software will prompt you to designate a file transfer protocol. The following table describes some of the most common protocols:
|
|
|
Protocol |
Description |
|
ZMODEM |
Transfers files in a streaming protocol, making it very
fast even with error |
|
YMODEM-G |
A variation of YMODEM designed for modems that support error control. Does not provide error correction or recovery, but relies on the modem to provide it. If any block is unsuccessfully transferred, the entire transfer is canceled. |
|
YMODEM |
An error correcting file transfer data transmission protocol that sends information in 1024-byte (1k) blocks. Checksums are done on each block and the result is sent along with the block. If the result does not check out at the receiving end, a NAK (Negative AcKnowledgement) is sent to retransmit that block. If the block checks out, an ACK (ACKnowledgement) is sent. |
|
XMODEM |
An error correcting file transfer protocol that sends informaton in 128-byte blocks. Checksums are done on each block and the result is sent along with the block. If the result does not check out at the receiving end, a NAK (Negative AcKnowledgement) is sent to retransmit that block. If the block checks out, an ACK (ACKnowledgement) is sent. |
|
KERMIT |
A very reliable asynchronous file transfer protocol that
can communicate |
|
ASCII |
Sends TEXT ONLY files directly to the computer screen. Is very slow. Binary or graphics files cannot be transferred using the ASCII protocol. |
Rules for Using File Transfer Protocols
For the best results when sending or receiving a file, follow these basic rules:
- If both systems support ZMODEM, use it!
- Both the sending and receiving modem must use the same file transfer protocol. BBS or online services usually inform you which protocols are available.
- Most communications software packages must be informed of the name of the sending (uploading) or receiving (downloading) file before file transfer can begin, and when a file transfer is about to take place. See your communications software manual for specific information.
CAUTION: When files are shared, the risk of getting a computer virus always exists. We recommend the use of virus scanning software to make sure the files you receive and send do not contain viruses.
Dialing
Most communications software allows for automatic dialing. See your software documentation for instructions.
To manually dial another modem, go into terminal mode in your communications software and type ATDT followed by a space and the telephone number.
When dialing, enter the same information you would if you were calling someone on the phone. For example, when dialing long distance, prefix the phone number with a 1 and the area code. If you are dialing from a telephone system that requires a 9 for an outside line, insert a 9 before the telephone number. You will probably need to place a comma or two after the 9 (9,,) to allow enough pause time to access the outside line. Each comma designates a two-second delay. Refer to S8 in the AT Commands, S-Registers, and Result Codes section in this guide.
Receiving a Data Transmission
A modem can answer a call in one of three ways: Host, auto-answer, or manual answer.
Host mode is a feature of the software, although it is not available in all communications software packages. Host mode allows the modem to answer the phone and place the caller into a "host" mode, allowing callers to download files, upload files, and chat with you while their modem is connected. Refer to your software documentation for instructions on how to use this feature.
Auto-answer is used to answer an incoming call without user intervention. The AT command for auto-answer is ATS=n, where n is the number of rings before the incoming call is answered. For example, ATS=2 tells the modem to answer after the second ring.
Manual answer tells the receiving modem not to answer when the phone rings. ATS must be set to 0 (ATS=0) when you are using manual answer. When the phone rings while you are in terminal mode in your communications software, the word RING will appear on the computer screen. You must then type ATA to tell the modem to answer. If the phone rings when you are not in terminal mode, you will neither hear nor see any indication that a call is coming in. If ATS= anything except 0, the Auto-Answer feature will be activated after the number of rings you specify.
Transmitting Faxes
Fax Cover Page
Your software may allow you to create a cover sheet to accompany your fax. Some fax software packages offer an option to customize a cover page. A cover page should give the person receiving the fax information about the fax, the sender, and the transmission. Most regulatory agencies require the following information to be displayed on either the top or the bottom of at least the first faxed page:
- Your name
- Your phone number
- Your fax number
- Date and time
You might also include the following information:
- Person you are sending the fax to
- That person's phone number
- That person's fax number
- Number of pages, including the cover sheet
- Your company, if applicable
Sending a Fax
Because each fax software package treats the faxing process differently, check the software user manual before sending a fax.
Opening the fax software loads the driver and prepares the modem to send the fax. If you are faxing from another application, you may have to create the fax, then go into the application's print setup menu to select the fax driver.
In North America, when entering a fax number, enter the same information you would if you were calling someone on the phone. For example, when you fax long distance, prefix the fax number with a 1 and the area code. If you are faxing from a telephone system that requires a 9 for an outside line, insert a 9 before the fax number. You may want to add a comma or two following the 9 (9,,) to allow enough time to access the outside line. Each comma adds a two-second delay to your dialing string. Refer to S8 in the AT Commands, S-Registers, and Result Codes section in this guide.
Receiving a Fax
Check your fax software manual to see how your fax software handles receiving faxes. Your fax software must be open for you to receive a fax. Windows fax packages may be opened and then minimized so you can receive a fax while working in another program.
Hints for Successful Faxes
- Avoid loading more than one fax package at a time on your computer. Because all fax software packages use the same types of files for operation, conflicts frequently occur if you have more than one fax program installed.
- Because many fax programs keep possession of the COM port after being loaded, you may need to unload the fax program in order to use other modem functions. Consult your communications software manual for instructions about unloading the fax program.
- In many Windows application packages, the fax driver is displayed among the printer selections in the Windows application software. Direct a fax to this driver to send it. Direct a received fax to your normal printer.