Everybody Needs AMODEM
A terminal program for your Atari
by JIM STEINBRECHER
AMODEM 4.2, a public-domain terminal program, requires 16K RAM for cassette and 24K RAM for disk use. To use it, you'll also need a modem, an Atari 850 Interface Moduale or equivalent, and Atari BASIC. It runs as is on all Atari computers, but cassette users must change the 400 in line 10000 to 2100.
AMODEM is a terminal program that, along with your Atari computer, a modem and an interface module, allows you to access all public bulletin boards, as well as time-sharing information services such as Compu-Serve and The Source. It features XMODEM protocol for easy uploading and downloading from many Atari and CP/M bulletin board systems (BBS's). XMODEM, written by Ward Christensen, is the only protocol that can be used to download tokenized BASIC (SAVEd) and binary file's.
To use AMODEM, type in the program and SAVE an extra copy as a back up. Then check for typing errors with TYYO (see "What Is a Typo Table?"). Before you RUN this program, you must load an RS-232 handler to provide a serial interface between your Atari and modem. Make sure that your 850 Interface is turned on, and boot your Master Disk with BASIC installed.
If you turn your TV volume up, you should be able to hear a one-second beep just hefore the READY prompt appears. This indicates that the RS-232 handler has been loaded. At this point, you can LOAD and RUN AMODEM. It takes a few seconds to initialize, after which the screen turns a darker shade of blue and the cursor appears.
To access a list of AMODEM's functions, press [SELECT]. To choose a function, press the letter that corresponds to the letter highlighted in the name of the function you want to use. Note that this isn't always the first letter in the function's name.
R -- Receive, Use this function to download files from another Atari or from a BBS that uses XMODEM protocol. If you're downloading from an Atari BBS that uses XMODEM, you'll be asked if you're using this protocol. Answer "Y" for yes. If you and a friend are transferring files between two Atari computers, both of you should be using AMODEM.
After you press [R], you'll be prompted to enter a file specification for the file to be downloaded. The file specification must include the device name and, if applicable, a file name (e.g., "D:FILENAME"). If you're using cassette, just type "Q". After you answer the prompt, the file is opened immediately, so make sure that your storage peripheral and media are properly prepared. Once you're back in terminal mode, simply press [START] (as promted by the BBS) if everrything is okay.
The rest of the download is automatic: the screen turns red and the file is received in 128-byte blocks. When the transfer has been completed, the file is saved, the screen turns blue, and you're returned once again to terminal mode.
U -- Upload. This function allows you to send files to another system that uses XMODEM protocol. The procedure is similar to that for downloading (see R above). After pressing [SELECT] and [U], respond to the prompt for an upload file specification, and AMODEM will read the file from the appropriate peripheral. Once you're back in terminal mode, press [START] and the file will be automatically transmitted.
C -- Capture. Use this function to download from a system that doesn't use XMODEM protocol, or simply to save received text. After pressing [SELECT] and [C], type in a file specification. If you press [OPTION] at this point, the screen turns black and the data you receive is printed to the screen and saved to the capture buffer.
You can toggle the capture feature on and off with the [OPTION] button to save selected portions of a transmitted text. If you want to clear the capture buffer without saving it (while retaining the file specification you originally noted), press [START]. When you've finished capturing the information you're after, press [SELECT], and then [D], and the data will be "dumped" to the file you previously specified.
S -- Send. Use this function to upload to a system that doesn't use XMODEM protocol. After you press [SELECT] and [S], type in a file spec and wait for it to be loaded into the buffer. When you're ready to send, press [START].
T -- Translation. This toggles between ATASCII (no translation) and ASCII (light translation) formats. Use ATASCII for hookups with Atari BBS's or between two Atari computers, and ASCII with all other systems. You must be in ATASCII to download or upload an Atari machine-language or tokenized BASIC file.
P -- Duplex. Use half duplex between two Atari computers, and full duplex for all others.
M -- Menu. Use [M] to get a directory listing from all on-line disk drives. For a directory from only one disk drive, press the appropriate number (1-4).
B -- Baud. AMODEM's default baud rate is 300. Use [B] to change this to either 600 or 1200 baud. You can use 1200 baud only for normal operation and with the Capture function -- BASIC is too slow to handle the others.
D -- Dump. See Capture above.
Jim Steinbrecher runs a popular BBS called A.R.C.A.D.E. at (313) 978-8087.
Listing: AMODEM.BAS Download