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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 #;
issue +++ escape code*
Examine diagnostics ( i11 )
Hangup. ( at h )
Dial another #.
Issue escape code ( +++ )
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)