hayes.txt

使用efax的fax工具程序

------------------------------------------------------------------------
S36      Bit 7-3=0       reserved 
First    Bit 2 (4)       If set, means try MNP protocol; reset means 
                         don't use MNP. 
Third    Bit 1 (2)       If set, means fall back to ASB; reset means 
                         direct async. 
Second   Bit 0 (1)       If set, means fall back based on Bit 1;
                         reset means hang up.
------------------------------------------------------------------------
         
The following table shows the meaning of each setting:

------------------------------------------------------------------------
S36=7   Try MNP, then fall back to ASB. 
S36=6   Try MNP, then hang up. 
S36=5   Try MNP, then fall back to direct async. 
S36=4   Try MNP, then hang up. 
S36=3   Don't try MNP; fall back to ASB. 
S36=2   Don't try MNP; hang up. 
S36=1   Don't try MNP; fall back to direct async. 
S36=0   Don't try MNP; hang up.
------------------------------------------------------------------------

There are three types of fallback stratagies which Hayes products use.

Type 1: Hayes Modem Operation in &Q5 Communications Mode
Applies to V-series Smartmodem 2400 up to and including Version 1.3 and 
V-series Smartmodem 9600 up to and including Version 1.4.

Type 2: Hayes Modem Operation in &Q5 Communications Mode
Applies to V-series Smartmodem 2400 Version 1.4 and V-series Smartmodem 
9600 Versions 1.5 and 1.6.

Type 3: Hayes Modem Operation in &Q5 Communications Mode
Applies to all V-series products newer than Types 1 and 2 and all OPTIMA 
and ACCURA EC products.
 
------------------------------------------------------------------------
               ATI3 Response contains...     
               V-SERIES SMARTMODEM 2400    V-SERIES SMARTMODEM 9600
Type 1         04-00005-10                 04-00015-10
               04-00005-11                 04-00015-11
               04-00005-12                 04-00015-12
               04-00005-13                 04-00015-13
                                           04-00015-14
Type 2         04-00005-14                 04-00015-15
                                           04-00015-16
Type 3         Does not contain any        Does not contain any
               of the above numbers        any of the above numbers
------------------------------------------------------------------------

************************************************************************
D.4  Connect Processing

Once the setup operation has been completed, the commands to establish 
the connection can be issued. The instruction can be either to originate 
(using the D command), or to answer (using the A or S0 commands).

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
D.4.1  Originating a Call

If the D command is issued with the desired phone number, several 
possible result codes can be returned. The list below outlines some 
results to expect:

Result Code        Meaning
------------------------------------------------------------------------
NO CARRIER         Connection failed
NO ANSWER          No response to '@' dial modifier
NO DIALTONE        No dial tone in X4 mode
NO ____            Connection failed for some other reason
BUSY               Busy signal detected
CONNECT ____       Connection successful; you may need to change DTE 
                   speed to the indicated baud rate. (See Wn and S95)
CARRIER ____       * DCE carrier speed. (See Wn and S95)
PROTOCOL: ____     * Error-correction protocol being used by the modems. 
                   (See Wn and S95)
COMPRESSION:____   Compression technique in use by modems. (See Wn 
                   and S95)
AUTOSTREAM         Autostream technique in use by modems if selected by 
                   user. (See Wn and S95)
------------------------------------------------------------------------

Ignore other responses, but continue to wait for CONNECT ___, BUSY, or 
NO ___ responses. The CARRIER and PROTOCOL results are intermediate 
results and precede either a CONNECT ____ or NO ____ result. These 
results are only returned by Hayes modems when configured to use an 
error-correcting protocol.

If you recognize any numeric value for the baud rate after the CONNECT 
result, you will have a much more robust controller able to handle many 
situations. You can use the PROTOCOL result to determine if the flow 
control requested by the &K command is in effect.

Note: If you want to manually dial a call and then have the modem connect, 
enter the command string ATX1D (X1 disables dial tone detection) when you 
hear the dial tone. 

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
D.4.2  Answering a Call

The simplest technique for answering an incoming call is to set S0 and 
wait for a CONNECT ___ result. You may get several RING results, and 
possibly a NO CARRIER result if the caller hangs up before connecting. 
These results should not cause your controller to abort. Continue to 
wait for a CONNECT result code.

If you set S0, you may want to set it back to zero after your controller 
finishes the call to prevent inadvertent answering when your software is 
not running. By setting S0 to the number of rings you desire before the 
modem answers, you utilize the ring detection technology already built 
into the modem.

You should not use the A command to answer after counting RING results 
because the command may collide with another RING result from the modem 
and be missed. The RING results may be generated in pairs depending on 
the ringing cadence of the phone system.

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
D.4.3  Using the CD Line

Monitoring the Carrier Detect (CD) line of the RS-232 interface is 
another technique for carrier detection in answer or originate mode. 
This assumes that &C1 or the corresponding DIP-switch has been set and 
the cable is wired properly. Both are risky assumptions. You will have a 
more robust controller if you use result code scanning rather than the 
RS-232 lines.

If you use CD, you do not know when the modem has given up waiting for 
the carrier, or why. If the line is busy, you may want to re-try the 
dial operation. If there is no dial tone, the user needs to know this.

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
D.4.4  Aborting a Connect Request

Once the D or S0 command has been issued, the modem goes off hook (or 
may be off hook for S0) and it must be put back on hook (hangPup) before 
the abort is completed. To abort an in-progress connect command, send 
any character to the modem. This will typically result in a NO CARRIER 
response. The result code scanner should be called after the abort 
character is sent to prevent additional commands from being sent before 
the controller and the modem are again in sync.

Smartcom products send AT<CR> to abort an in-progress connect command. 
This elicits a result code regardless of whether the modem were off-hook 
or not. If the modem was off-hook attempting to connect, this will abort 
the connect operation and return NO CARRIER. If the modem was on-hook in 
command mode, this simply returns <CR><LF>OK<CR><LF>.

************************************************************************
D.5  Carrier Loss Detection

You want your application to be able to detect when the carrier has been 
lost so you can determine when the connection is complete. You might be 
unable to put this part of the code in your controller software, since 
the controller is typically running only during the connect or hang-up 
process. Once the application has detected the carrier loss event, it 
can call the modem controller and restore the modem settings.

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
D.5.1  Using the CD line

If you are confident of the communications environment and cabling 
requirements, and have access to the RS-232 signal status, then 
monitoring the CD line is the easiest carrier loss detection method to 
implement. This requires &C1 to be programmed at setup time, or be 
stored in the modem as the value recalled on reset or power-up.

However, this is the most restrictive and risky choice. It requires a 
properly wired cable and support of &C1 by the modem's command set or 
proper DIP-switch settings.

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
D.5.2  Scanning the Incoming Data Stream

In cases where you  cannot depend on 100% Hayes compatibility or want to 
be independent from the cable wiring, then scanning for the NO CARRIER 
result code is more reliable. It is also more complex to implement.

Typically, at the low-level of the program all received data is 
retrieved through one subroutine. This subroutine can be augmented or 
layered to provide the service needed. As data passes through, the last 
fourteen characters are buffered, typically in a circular buffer. If 
more data passes in each call, only the last fourteen need to be copied. 
At a time when the processor is free, such as after 100 ms of idle time 
or the receive routine has returned no data for 30 to 100 calls, then 
the buffer is compared against the <CR><LF>NO CARRIER<CR><LF> result 
code. If a match is found, the carrier lost event is triggered.

By only checking when there is idle time, or after no data has been 
received for a while, you reduce the CPU overhead and ensure that the 
modem is not falsely triggered when the string is imbedded in an actual 
data stream.

You can also modify the linefeed character by using S4 to a different 
value such as S4=31 to make the result code sequence more unique. This 
action, however, affects other result codes generated by the modem.

************************************************************************
D.6  Escape and Hang Up

When your controller has been instructed to terminate the connection, 
you must put the modem back in command state and issue the hang-up (H) 
command. In addition to hanging-up, you will also want to restore 
settings you changed to their factory-set values, or issue an ATZ<CR> to 
undo the effects of your changes. In any case, restoration of the modem 
settings is necessary even if the connection was terminated due to loss 
of carrier.

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
D.6.1  Escaping the Modem to Command State

To escape the modem, the controller must first delay the escape sequence 
guard time (specified by S12), then issue the escape sequence character 
three times (specified by S2); then wait for an OK result. Waiting for 
the result also enforces the required guard time after the escape 
sequence. Once the OK result is received, the modem has entered command 
state. The controller can then hang up and restore the modem.

The controller software must be sure to wait the required guard time 
before sending the escape sequence characters. Your controller may have 
been called just after data was transmitted and, without the delay, your 
characters will just be sent without triggering the escape sequence 
recognition process. It is important that the serial transmitter be 
permitted to be idle for the escape sequence guard time, plus a few 
extra milliseconds to allow for error, before sending characters.

For example, if  S12=10, a delay of at least 200 milliseconds is 
required before sending the escape sequence characters. After sending 
the escape sequence characters, the OK result will be received after 
another 200 millisecond wait. This completes the escape sequence process 
in slightly over 400 milliseconds. If S12=50 (factory setting) is used, 
one full second must pass before the characters can be sent, then 
another second delay must transpire prior to the OK result. This 
completes the process in slightly over two seconds. For this reason, it 
is recommended that S12=10 be issued to speed up this process.

A delay slightly longer than that stored in S12 should be used to allow 
for errors in the system clock as well as in the modem clock. 100ms is 
an adequate safety margin.

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
D.6.2  Using DTR to Escape or Hang Up

The DTR RS-232 signal can be used to escape the modem to command state, 
or to reset the modem depending on the &D command set or DIP-switch 
settings. This also requires the cable to be properly wired. Unless the 
software will operate in a highly-controlled environment, this technique 
is discouraged over using the escape sequence process because of the 
requirements to make it function properly. Leaving a call connected 
simply because the cable was not properly wired can be potentially 
expensive. The escape sequence is reliable in all environments if it is 
properly utilized.

************************************************************************
D.7  Modem Re-configuration

When a call has been completed, a "clean-up" command should be issued to 
return the modem a more known configuration. For example, if verbose 
result codes were selected when the modem was reset, and the controller 
selected numeric result codes, on completing the session, the controller 
should reset the modem to re-select verbose result codes. In the same 
way, if the linefeed character were changed to suit the software or 
environment, the character should be set to its former value. Any other 
command options that were modified, should be restored to their factory-
set values.

The minimum the controller should do when through with the modem is 
issue a Z command option to ensure the modem is restored to its power-up 
state.

************************************************************************
D.8  Timing Considerations

A modem controller inherently has a sense of time. Usually all that is 
needed to utilize the timing part of the controller is access to a time 
reference. For example, the number of milliseconds since power-up or 
program launch, or a "system tick" value can be used. 

Under DOS, the INT 1C timer tick produces an interrupt every 55 
milliseconds. An ISR can be installed on this interrupt to add 55 to a 
long integer every time it is called. This will provide a millisecond 
counter.

On the Macinto