Using HyperTerminal

Now that you have HyperTerminal directly connected to your modem, you can control it, test it and examine its diagnostics with the appropriate AT commands.

All modems share some commands.

AT returns OK.

AT DT is the command to tone dial a number.

+++ is escape to command mode*

AT H = hangup

The screenshot above shows 2 local calls made with USR 56k external modem. Note, most modems set to factory default command is AT&F. Most 3Com modems provide 2 factory defaults, and &F1 is appropriate for 56k, error-correction on connections. Note that the first attempt only produced a 36000 connect, while the second, 49333.

The pane to the right is a HyperTerminal session with the LT modem -
Set to factory defaults;
Dial local #;
CONNECT;
issue +++ escape code*
Examine diagnostics ( i11 )

Hangup. ( at h )

Dial another #.

Connect.

Issue escape code ( +++ )

Examine diagnostics.

at&f
OK
atdt9345202
CONNECT 49333 V42bis

OK
at i11

    Description                         Status
    ---------------                     ------------
    Last Connection                     V.90
    Initial Transmit Carrier Rate       28800
    Initial Receive  Carrier Rate       49333
    Final   Transmit Carrier Rate       28800
    Final   Receive  Carrier Rate       49333
    Protocol Negotiation Result         LAPM
    Data Compression Result             V42bis
    Estimated Noise Level               105
    Receive  Signal Power Level  (-dBm) 10
    Transmit Signal Power Level  (-dBm) 12
    Round Trip Delay             (msec) 4
Press any key to continue; ESC to quit.

    Description                         Status
    ---------------                     ------------
    Near Echo Level              (-dBm) NA
    Far  Echo Level              (-dBm) NA
    Transmit Frame Count                3
    Transmit Frame Error Count          0
    Receive  Frame Count                0
    Receive  Frame Error Count          0
    Retrain by Local  Modem             0
    Retrain by Remote Modem             0
    Call Termination Cause              0
    Robbed-Bit Signaling                00
    Digital Loss                   (dB) 3
    Remote Server ID                    NA

OK
ath
OK
atdt9616616
CONNECT 50000 V42bis

UQKT2 tnt1.hilo.hi.gt.uu.net

Login: +++
OK
at i11

    Description                         Status
    ---------------                     ------------
    Last Connection                     56K
    Initial Transmit Carrier Rate       26400
    Initial Receive  Carrier Rate       50000
    Final   Transmit Carrier Rate       26400
    Final   Receive  Carrier Rate       50000
    Protocol Negotiation Result         LAPM
    Data Compression Result             V42bis
    Estimated Noise Level               117
    Receive  Signal Power Level  (-dBm) 29
    Transmit Signal Power Level  (-dBm) 16
    Round Trip Delay             (msec) 4
Press any key to continue; ESC to quit.

    Description                         Status
    ---------------                     ------------
    Near Echo Level              (-dBm) NA
    Far  Echo Level              (-dBm) NA
    Transmit Frame Count                3
    Transmit Frame Error Count          0
    Receive  Frame Count                5
    Receive  Frame Error Count          0
    Retrain by Local  Modem             0
    Retrain by Remote Modem             0
    Call Termination Cause              0
    Robbed-Bit Signaling                00
    Digital Loss                   (dB) 3
    Remote Server ID                    4347C4

OK

This is a session with the USR modem dialing a number, then examining the i6 diagnostic screen.

atdt 9345209
CONNECT 49333/ARQ
at
OK
ati6
U.S. Robotics 56K FAX EXT Link Diagnostics...

Chars sent                    3      Chars Received                0
Chars lost                    0
Octets sent                   3      Octets Received               0
Blocks sent                   3      Blocks Received               0
Blocks resent                 0

Retrains Requested            0      Retrains Granted              0
Line Reversals                0      Blers                         0
Link Timeouts                 0      Link Naks                     0

Data Compression       V42BIS 2048/32
Equalization           Long
Fallback               Enabled
Protocol               LAPM/SREJ
Speed                  49333/28800
V.90 Peak Speed        49333
Last Call              00:00:11

Disconnect Reason is DISC Received
ath

* - Escape code sequence - once you have gotten a CONNECT message, if you type 3 plus signs, the modem will stay connected and enter command mode. You go back to data-online mode with the ATO command. The + signs will not be echoed back to you - you do not see them on the Hyperterminal display.
Commands nearly every modem recognizes:

ATs0 = # - # of rings to auto-answer after; if 0, disable auto-answer
AT A = Answer call
AT D = Dial
AT E# = Echo characters in command mode - where # = 0-no echo; 1=echo
AT H = Hangup
AT M# = Modem speaker: # = 0 - speaker off; 1 - speaker on during handshake; 2 - speaker always on
AT O = Go online
AT X# = Result codes / blind dialing - # = 0 or 1 to disable speed reporting, dial-tone detect, etc.
AT Z = reset modem
AT &F = reset modem to factory defaults
AT s6 = # - # of seconds modem waits before dialing after going off-hook
AT s7 = # - # of seconds modem waits for carrier after dialing
AT s10 = # - Durations in 1/10th second modem waits before hang-up after loss of carrier
AT s11 = # - Duration in milliseconds of tone dialing
AT s2 = ### - ASCII escape code character - defaults to 43 which is the plus sign ( + )
AT s12 = ### - Duration, in 50ths of a second, of guard time for escape code sequence (default = 50)