Electronics Is Fun GURUMODEM, Manual

Page 1: ...GURUMODEM RS 232 Wifi Modem The Gold Standard in RS 232 WiFi Communications From Electronics Is Fun www ElectronicsIsFun com Febuary 23 2019 ...

Page 2: ...ing the GuruModem Card 4 AT CONFIG usage 7 AT CONFIG Menu options 8 BBS SUB MENU options 8 AT Shell usage 9 Command usage 10 Communications 12 Advanced topics 13 FTDI Cable Download 13 Over the Air Download 15 AT Command Reference 16 Schematics 24 Board Layout 29 GLOSSARY 30 ...

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Page 4: ...cations software or custom built serial communications software Additionally the user can also connect to other computers and BBSs over the Internet or directly to other computers using TelNet The GuruModem can be programmed using AT commands that are similar to the Hayes modem command set used with phone line modems The GuruModem also provides on board storage via a micro SDCARD The onboard firmw...

Page 5: ...se cases an adapter and or a gender changer will be required FEATURES Full standard RS 232 interface with Modem Control Integrated WiFi and Bluetooth ESP32 module Onboard mini SD CARD interface On board low dropout regulator Over The Air firmware updating Debug interface 3 3V TTL signaling Built shell with DOS Linux type commands Support for multiple protocols Support for Xmodem and Zmodem transfe...

Page 6: ... you may need to use a serial cable adapter etc 4 Some computers require using the appropriate serial cable adapters etc Connect one end of the cable to the serial port on the computer Note On most computers a cable and or adapters are not required 5 Connect the other end of the cable to the DB 25 connector on the GuruModem 6 Install a FAT32 formatted mini SDCARD 7 Connect the 5V power adapter to ...

Page 7: ...nge parameters and configuration options The AT CONFIG command provides a series of menus to configure the GuruModem quickly In this section we describes some of the more common AT commands and how they can be used to get the most out of the GuruModem card Additional commands can be found in the AT Command Reference Set the baud rate The default baud rate is set to 1200 baud If you want to change ...

Page 8: ...II The GuruModem card can understand PETSCII used by commodore computers and ASCII However under certain situations sending PETSCII to the GuruModem can result in an error This occurs because the GuruModem can only interpret commands in ASCII For example when setting the SSID and password if the computer is in commodore graphics PETSCII mode an error will be generated It is for this reason that th...

Page 9: ...ommand is helpful when trying to connect to a different network Note this command only works if you have already configured your SSID and password Reset to factory settings You can reset the GuruModem card back to factory setting by issuing the following command at f This command will erase any settings that were configured by the user back to the default settings that were set at the factory BBS ...

Page 10: ... form of Ipaddress port In some cases the telnet address is the name URL of the BBS Also some telnet address do not require a port number AT CONFIG USAGE The easiest way to configure the GuruModem is to issue the AT CONFIG command This command provides features to configure GuruModem using a clear and concise menu Some of the meu options have submenus to make addition selections To use this menu t...

Page 11: ...option is issued a submenu will be displayed Typing ENABLE will show the submenu to configure the BBS parameters HOST PETSCII TELNET ECHO FLOW and DISABLE This menu allows the user to setup the modem to accept an internet connection This is like a modem that is in auto answer mode When an attempt is made to connect to the GuruModem from the Internet on a specific port the modem will accept the con...

Page 12: ...w entry to the phonebook to allow quick connections over the internet to BBSes or Telnet servers With the ADD option the user can enter a number and the ipaddress port of a BBS or server to be accessed This creates a quick dial number that can be used to quickly connect to other machines Some older communications software require a number to be dialed instead of accepting the ipaddress port Once y...

Page 13: ...les cd path Change to new directory md mkdir makedir path Create a new directory rd rmdir deletedir path Delete a directory rm del delete r path filename Delete a file cp copy r f path filename path filename Copy file s ren rename path filename path filename Rename a file mv move f path filename path filename Move file s cat type path filename View a file s df free info Show space remaining xget z...

Page 14: ...lenames and switches like r and f Getting a file using fget the user must specify the ipaddress or URL file source address and file destination If the connection to the ftp server is not anonymous the user name and password must also be specified The full path along with the filename must be specified as shown below ls r ls games action arcade cd games cd mkdir games strategy deletedir games text_...

Page 15: ...her computers on a local network or across the Internet The protocol available depend on the types of communications software provided by the user Some popular protocols available include but are not limited to the following list XMODEM YMODEM ZMODEM FTP IRC TelNet Etc ...

Page 16: ...environment to build the firmware The repository for the firmware source is available at https github com bozimmerman Zimodem The GuruModem card is based on the ESP WROOM 32 by Expressif This is a feature rich WiFI module that contains 4MB of flash onboard This flash can be updated using the Arduino IDE It can also be updated over the air using an AT command To perform the updates the following in...

Page 17: ...ment and your firmware files are stored Three files are supplied with the Arduino IDE esptool exe boot_app0 bin bootloader_qio_80m bin Two files will be generated from your build of the firmware zimodem ino bin zimodem ino partitions bin The FTDI model TTL 232R 3 3V cable is required Configuring the hardware for firmware downloading The GuruModem card must be connected to the computer over an FTDI...

Page 18: ...em you must configure your software to run at the same baud rate Issuing the following command will perform the update from the default server AT U6502 Will update the firmware from the home page on the web AT U x Will update the firmware from the web to custom version x The over the air update restricts the size of the update to 512K bytes or less If you are building a custom firmware that is lar...

Page 19: ...ings all S registers ATA If a server listener has generated a RING then ATA will switch the last rung connection to Stream mode see ATD ATA Repeats the previous command no idea why ATAn Causes the modem to create a server listening on port n When a connection is received the terminal will generate 1 or more RINGs according to the ATS0 register followed by a normal CONNECT response At this point al...

Page 20: ...T 2 instead of 1 CONNECT etc ATF0 Turns on rts cts flow control ATF1 Turns on xon xoff flow control ATF2 Turns on xon xoff flow control sets XON mode if necessary and in command mode will immediately go to XOFF when a single connection packet is received This is very useful when the client wants to ensure it only receives one packet to process You can think of this as an alternative way to use xon...

Page 21: ...rt a streaming connection between the current opened connection Use to exit back to Command mode ATDn Where n 0 this will start a streaming connection between the previously opened connection with an id the same as n Use to exit back to Command mode ATD HOSTNAME PORT This opens a streaming connection between the terminal and the given host port Use to disconnect and exit back to command mode ATDP ...

Page 22: ...ing a T modifier causes streaming input to be translated per TELNET when the changed to Stream mode ATCE HOSTNAME PORT Adding an E modifier causes terminal echo to be enabled when the changed to Stream mode ATCX HOSTNAME PORT Adding a X modifier causes XON XOFF flow control to be enabled when the changed to Stream mode ATH Hangs up disconnects and deletes all open connections Does not close Server...

Page 23: ... RING messages received before a CONNECT response is sent on incoming Server listeners ATS1 n Unimplemented always returns OK ATS2 n Change the escape character n 0 255 Defaults to ASCII decimal 43 ATS3 n Change the Carriage Return Character n 0 127 Defaults to ASCII decimal 13 Carriage Return ATS4 n Change the Line Feed Character 0 127 Defaults ASCII decimal 10 Line Feed ATS5 n Change the Backspa...

Page 24: ...LOW active N A on ESP01 ATS49 n Changes DCD pin number n 2 is default ATS50 n Changes CTS pin number n 0 is default on ESP01 and default is 5 otherwise ATS51 n Changes RTS pin number n 4 is default N A on ESP01 With a 1 second pause with no other characters afterwards this will disconnect the current opened connection ATT MESSAGE Transmit the given text string with r n at the end on the current co...

Page 25: ...date the firmware from the home page on the web BETA AT U x Will update the firmware from the web to custom version x AT Pn Where n 0 all command mode input and output will be translated to from PETSCII before internal processing This will not affect received packet data or the stream mode AT Nx Shows the status of ESP32 I O pin x AT Mn Adds the byte denoted by n to a list of mask out bytes These ...

Page 26: ...n 8 bit sum of all the bytes in the forthcoming file followed by the bytes of the file all formatted as a normal packet An ASCII 3 CNTRL C received during the transfer will abort The S44 register can be used to create artificial delays in this output XON XOFF Flow control also remains in effect with on a byte by byte basis for the auto and manual flow control systems AT CONFIG Displays the configu...

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Page 32: ...29 BOARD LAYOUT ...

Page 33: ...unique address that is usually 4 bytes long for example 192 168 1 100 WiFi The wireless standard defined as 802 11a b g or n BBS Bulletin Board System Bootstrap A small program that starts the process of loading other larger programs or an operating system FTP File Transfer Protocol used to send and receive files over the Internet Telnet A protocol used to connect to other machines or servers over...

Page 34: ...16 ATDP 16 ATDT 16 ATE0 15 ATE1 15 ATF0 15 ATF1 15 ATF2 15 ATF3 15 ATH 17 ATH0 17 ATHn 17 ATI 14 ATI1 14 ATI2 14 ATI3 14 ATI4 14 ATI5 14 ATN0 15 ATO 17 ATP 16 17 18 ATPE 18 ATPP 18 ATPT 18 ATPX 18 ATQ0 15 ATQ1 15 ATR0 16 ATR1 16 ATR2 16 ATR3 16 ATS0 14 18 ATS1 18 ATS2 18 ATS3 18 ATS4 18 ATS40 18 21 ATS41 14 18 ATS42 18 ATS43 18 ATS44 19 ATS45 19 ATS46 19 20 ATS47 19 20 ATS48 19 ATS49 19 ATS5 18 AT...

Page 35: ... SSID and passward for your network 5 Display available hotspots networks 6 FTDI Cable Download 8 Getting help 5 Getting Started 3 Over the Air Download 10 PETSCII vs ASCII 5 Reset to factory settings 6 Saving your SSID and password 5 Schematics 22 Set the baud rate 4 TELNET 14 16 17 18 ...