1. Handshaking
2. Valid Baud Rates
3. Valid Parity Rates
4. Valid Data Bit Values
5. Valid Stop Bit Values
6. Standard Modem Commands

Comments

1. eky
   24 Aug 2004 at 13:53

   Hi U
   Can U  show me some page ,apllicate this code by VB . U can send my mail kychinh2002@yahoo.com
   thanks,i need it so much

2. eky
   24 Aug 2004 at 13:52

   Hi U
   Can U  show me some page ,apllicate this code by VB
   thanks,i need it so much

3. jainsapna
   04 Aug 2004 at 04:40

   i am using mscomm with visual basic. i want to read/write data on serial port rs232. what code will i have to write and what properties i will have to change in mscomm. please help me as soon as possible.

4. vbgeek
   03 Mar 2004 at 22:16

   However, i think you need to perfect it more on a particular section ....
   

   
   Do you know what command to issue so that when i call up the receiver's HP, i can get to know whether the receiver phone is ringing? and count the number of times the phone ring?? get i get those reponse? cause i am trying to do a miss call.
   In order to do that i need to know whether the phone rings .. if so i will let the phone ring for 3 times ... then hang up
   ..
   

   
   
   

   
   Another question is :
   

   
   comEvRing "6"
   Ring detected. Some UARTs (universal asynchronous receiver-transmitters) may not support this event.
   

   
   i understand that the above means that ring is detected. when the CommEvent is "6". However, what does it mean some UARTs may not support it ...
   

   
   Can any expert show me what that means? i dont seem to understand it.
   

   
   and my current modem is :
   3COM US ROBOTICS 56K FaxModem Model (455630-01)
   

   
   does my modem support that?
   

5. fycz
   16 Dec 2003 at 22:45

   do your problem has solved?
   I meet the same problem now, visual basic text doesn't give any response to binary input.
   

   
   I really need your solution, if you already have it
   

   
   thanks

6. lackey
   02 Sep 2003 at 13:23

   
   Modem CODES AT Attention Code. Must appear at start of all commands except A/ and +++.
   A Answer Command. Answer incoming call.
   A/ Repeat Last Command.
   Bn Bell Compatibility
   B,B0 Variable connection rate ITU-T (CCITT) Compatibility.
   B1 Variable connection rate Bell Compatibility.
   B2 Auto-mode V.22/Bell 212A protocols.
   B4 300 bps Bell 103 protocol.
   B5 1200 bps V.22/Bell 212A protocols.
   B6 2400 bps V.22/bis protocol.
   B7 4800 bps V.32 protocol.
   B8 9600 bps V.32 protocol.
   B9 14,400 bps V.32 bis protocol.
   Ds Dialing Command
   DP Dialing Command. Pulse Dialing.
   DR Dialing Command. Reverse.
   DS Dialing Command. Dial one of the srored numbers.
   DT Dialing Command. Tone Dialing.
   D@ Dialing Command. Wait for 5 seconds quiet.
   D, Dialing Command. Pause.
   D; Dialing Command. Resume command mode after dialing.
   D! Dialing Command. Hook Flash.
   E Echo Command
   E,E0 Echo Off.
   E1 Echo On.
   Hn Switch-Hook Control.
   H,H0 On Hook (hang up phone).
   H1 Off Hook (pick up phone).
   In Request Product Code and Checksum.
   I,I0 Return Product Code.
   I1 ROM checksum, product ID, ROM version number.
   I2 Compute ROM checksum.
   I3 Error Correctio Code.
   I4 Product ID, ROM version number, modem chip type, fax operatnig mode.
   Ln Speaker Volume
   L,L0,L1 Speaker Volume. Low Volume.
   L2 Speaker Volume. Medium Volume.
   L3 Speaker Volume. High Volume.
   Mn Monitor on/off
   M,M0 Speaker off.
   M1 Speaker on until online.
   M2 Speaker always on.
   M3 Speaker on until online and off while dialing.
   On Return to online mode.
   O,O0 Return to online mode.
   O1 Return to online mode and start retrain sequence.
   O2 Fall forward. Return to online mode.
   O3 Fall back. Return to online mode.
   P Pulse dialing.
   Qn Quiet Command
   Q,Q0 Display result codes.
   Q1 Don't display result codes.
   Q2 Display result codes when originating a call.
   Q3 Return numeric results 32 and 30 for CONNECT 9600 and CONNECT 4800.
   Q4 Return numeric results 12 and 11 for CONNECT 9600 and CONNECT 4800.
   Sr Direct Register Command
   Sn Select register n as default register.
   Sn? Read and display value in register n.
   Sn?^ Read and display value in register n in HEX.
   Sn=N Set register n to value N.
   Sn=N^ Set register n to value N in HEX
   Vn Verbal/Numeric Result Codes.
   U Update System password.
   V,V0 Numeric Result Codes.
   V1 Verbal Result Codes.
   Xn Enable Extended Result Code
   X,X0 No wait for dial tone. No busy. CONNECT 0-4 returned.
   X1 No wait for dial tone. No busy. CONNECT 0-5 and 9-20 returned.
   X2 Wait for dial tone. No busy. CONNECT 0-6 and 9-20 returned.
   X3 No wait for dial tone. Busy recognized. CONNECT 0-5,7 and 9-20 returned.
   X4 Wait for dial tone. Busy recognized. CONNECT 0-7 and 9-20 returned.
   Y Long Space Disconnect
   Z Reset Command
   &V Display al stored profiles.
   &Zn=s Store telephone number.
   +++ Escape Code. Switch from data mode to command mode.
   

   
   thanks to Oliver Lawrence lawrence@cdnet.cod.edu <lawrence@cdnet.cod.edu>

7. Heng Sieu Lee
   06 Aug 2003 at 21:55

   Good Day,
   

   
   I'm using VB6 MSComm with "2400,n,7,1" (settings) to dial up using ArtNet modem. I couldn't get any dial tone with the mentioned setting. However, when i change to "2400,n,8,1" it will be able to dial up ? When i use hyperterminal with "2400,n,7,1" to dial up, no problem at all. Any idea what's wrong ? Thanks in advance.

8. Voodoo Attack!!
   16 Jun 2003 at 22:06

   Hiii
   

   
   I really loved this article, nice one!
   

   
   Here is a complete list of all the AT commands I could get..
   

   
   

   
   Table 1. Basic Data Modem AT Commands

   
   

   
   

   
   A/    Repeat the last AT command string issued.
      An “AT” prefix is not used. Do not terminate this command
      with <ENTER>.
   

   
   A    Answer.
      Go off-hook and enter the answer mode. After 3 seconds the
      modem will initiate an answer tone.
   

   
   Bn    ITU-T or Bell® (Default=1)
   

   
      B0    Use ITU-T V.22 at 1200 bps, and ITU-T V.21at 300 bps
      B1    Use Bell® 212A at 1200 bps, Bell® 1035 at 300 bps.
      B2    Use ITU-T V.23 only. The originating modem transits at 75
          bps (and receives at 1200 bps); the answering modem receives
          at 75 bps (and transmits at 1200 bps)
      B3    Selects ITU-T V.23 only. The originating modem transmits at
          1200 bps (and receives at 75 bps); the answering modem
          receives at 1200 bps (and transmits at 75 bps)
   

   
   Cn    Carrier control option (Default=1)
   

   
      C0    Transmit carrier always off
      C1    Normal transit carrier
   

   
   

   
   D    Dial command
   

   
   

   
   En    Command Echo (Default=l)
   

   
      E0    Disables command echo from the modem.
      E1    Enables command echo from the modem.
   

   
   Fn    Online echo (Default=1)
      
      F0    Enables online echo
      F1    Disables online echo
   

   
   Hn    Hook Switch Control (Default=0)
   

   
      H0    Hangs up the telephone line
      H1    Picks up the telephone line
   

   
   In    Identification/checksum option (Default=0)
      I0    Reports product code
      I1    Reports modem chip firmware version
      I2    Verifies ROM checksum
      I3    Reports device set name
      I4    Reserved
      I5    Reserved for modem chip hardware configuration
      I6    Country code
      I7    Version of board manufacturer firmware
      I8    Features of modem firmware
      I10    Modem board configuration - bit set by board manufacturer
      I11    Modem board configuration - bits set by board manufacturer
      I14    SAFE device
      I20    Cirrus Logic silicon version
      I21    Cirrus Logic firmware version
      I22    Cirrus Logic manufacturer name
      I23    Cirrus Logic product model
      Ln    Speaker Volume control (Default=2)
      L0,1    Low volume.
      L2    Medium speaker volume
      L3    High speaker volume
   

   
   Mn    Speaker On/Off (Default=1)
      M0    Speaker off.
      M1    Speaker on until modem detects the carrier signal.
      M2    Speaker is always on when modem is off-hook.
      M3    Speaker off during dialing, on until modem carrier present
   

   
   Nn    Select data rate handshake (Default=1)
      N0    Handshake only at DTE-to-modem data rate
      N1    Begins handshake at DTE-to-modem data rate and falls to
          highest compatible rate
   

   
   On    Go Online (Default=0)
      O0    Returns modem to data mode
      O1    Retrains equalizer and then returns to data mode
   

   
   P    Pulse Dial
   

   
   Qn    Result Codes (Default = 0)
      Q0    Enables display of result codes
      Q1    Disables display of result codes
   

   
   Sn    Select an S-register
      Sn=x    Write to an S-Register
      Sn?    Read from an S-Register
   

   
   T    Tone Dial
   

   
   Vn    Result Codes Format (Default=1)
      V0    Enable short-form result codes. (Numeric)
      V1    Enable long-form result code. (Text or Verbose)
   

   
   Wn    Response code data rate (Default=0)
      W0    Reports DTE speed response codes
      W1    Reports DTE speed response codes
      W2    Reports DCE speed response codes
      W3    Reports DTE speed response codes and information on error
          correction and data compression
   

   
   Xn    Result Code type (Default=4)
      X0    Enables result codes 0-4; disables detection of busy and dial
          tone
      X1    Enables result codes 0-5, 10, and above; disables busy and dial
          tone detection
      X2    Enables result codes 0-6 and 10 and above; disables busy
          detection and enables dial tone detection
      X3    Enables result codes 0-5, 7, and 10 and above; enables busy
          detection and disables dial tone detection
      X4    Enables result codes 0-7 and 10 and above; enables busy and
          dial tone detection
   

   
   Yn    Long Space Disconnect (Default=0)
      Y0    Disable Long Space Disconnect
      Y1    Enable Long Space Disconnect
   

   
   Zn    Recall stored profile (Default=0)
      Z0    Resets modem and recalls user profile 0
      Z1    Resets modem and recalls user profile 1
   

   
   &Cn    DCD (data carrier detect) option (Default=1)
      &C0    Ignores remote modem status; DCD always on
      &C1    DCD set according to remote modem status
   

   
   &Dn    DTR Control, Data Terminal Ready (Default=2)
      &D0    In async mode, modem ignores DTR
      &D1    Modem switches to command mode when DTR switches on
      &D2    When DTR switches off, the modem goes on-hook and
          disables auto-answer mode; when DTR switches on, autoanswer
          is enabled
      &D3    Turning off DTR re-initializes the modem and resets values
          except UART registers
   

   
   &F    Load factory defaults
   

   
   &Gn    Guard tone option (1200 bps and 2400

9. hoangminh
   25 Apr 2003 at 05:57

   I've used MSCOMM on Visual Basic to receive binary data from my own equipment (I've creative it).
   Even if I use Binarymode but my data was received is not format that my equipment was send. (My data can't converted by Cint() or Cbyte(), only Val() can converted it but result is zero).
   How I can receive binary data by MSCOMM?

10. José Manuel Sánchez Rodríguez
    19 Apr 2003 at 14:05

    http://www.angelfire.com/linux/jsanchez/NullmodemCables.htm
    

    
    SEND ME AN EMAIL FOR GIVE MORE BEST TECHNICAL HELP.
    

    
    GOOD DAY!!! AND HARE KRISHNA

11. José Manuel Sánchez Rodríguez
    19 Apr 2003 at 13:24

    you need know how make a null modem cable?

12. tongston
    19 Mar 2003 at 10:15

    I want to communicate throught the com1 port using a Null modem cable. I need help in this regard.

13. takhan
    24 Dec 2002 at 07:39

    i am using MSComm with Visual Basic . it does not read or write anything on the port. i dont have modem in my pc. i only want to read data from serail port rs232. i am using a time and attandance recorder which sends data on com1 and shows it on its software but when i read it with MSCOmm it shows nothing. Mscomm1.intBufferSize is o . please help me soon.

14. andre aham
    02 Jul 2002 at 06:37

    I want to design 2 programs Client /server which comunicate thru phone line, using MScomm Control.
    But i don't know how to make Mscomm waiting for a call like We do with Winsocket.
    could you kindly help me?

15. Developer Fusion Bot
    01 Jan 1999 at 00:00

    This thread is for discussions of Com Ports - Technical Information.