Table 24. Fax Mode Command Descriptions (Continued)

Fax Class 1 AT Commands

Table 24. Fax Mode Command Descriptions (Continued)

Command

Default

Description

 

 

 

 

 

Receive HDLC Data: The +FRH=<mod> command causes the modem to receive

 

 

HDLC-framed data using the modulation mode selected in <mod>. The modem then

 

 

delivers the next-received frame to the DTE.

 

 

If the modem detects the selected carrier signal with an HDLC flag, the modem sends

 

 

a ‘CONNECT’ result code to the DTE. If the modem detects a different signal, the

 

 

modem sends the ‘+FCERROR’ (fax connect error) result code to the DTE and returns

 

 

to command mode. Upon loss of carrier, the modem returns to command mode and

 

 

sends a ‘NO CARRIER’ result code to the DTE.

 

 

After receiving the HDLC flags, the modem strips away the flags and buffers the

 

 

received frames. The modem then transfers the received data to the DTE, starting with

 

 

the first non-flag byte and continuing through the last FCS byte. The DTE should

 

 

ignore the value of the FCS bytes. The modem also performs HDLC zero-bit deletion

 

 

and error checking.

 

 

After the FCS bytes are transferred, the modem marks the end of the frame with

 

 

<DLE><ETX> and reports the status of the frame reception to the DTE. If the frame

+FRH=m

none

was received correctly (FCS is correct), the modem returns a ‘OK’ result code. If the

frame was received in error (FCS is not correct, carrier lost, or data lost due to data

 

 

overflow), the DCE returns an ‘ERROR’ result code. The DTE should then discard this

 

 

frame.

 

 

After sending the status result code, the modem is ready to accept new commands

 

 

from the DTE.

 

 

The modem obeys the configured flow control from the DTE. If the DTE sends any

 

 

character to the modem other than DC1 or DC3 while the modem is in this mode, the

 

 

modem enters command mode and return an ‘OK’ result code.

 

 

After sending the result code indicating that frame reception is complete, the modem

 

 

continues to receive and buffer the data in the selected mode. If the DTE issues

 

 

another +FRH=<mod> command, the modem returns another ‘CONNECT’ result

 

 

code and continues with HDLC reception. If the DTE issues any command that

 

 

changes modulation, the DCE stops the receive process; the DCE then discards any

 

 

buffered data and processes the command.

 

 

Range: <mod> = 3

 

 

Refer to Table 23 on page 65.

 

 

 

 

 

Receive Data: The +FRM=<mod> command causes the modem to enter receive

 

 

mode using the modulation scheme specified in <mod>. <mod> may have the values

 

 

shown in Table 23 on page 65.

 

 

When the selected carrier is detected, the modem sends a ‘CONNECT’ result to the

 

 

DTE. If a different signal is detected, the modem sends a ‘+FCERROR’ (connect error)

 

 

result code to the DTE and returns to command mode.

 

 

After receiving the selected carrier, the modem transfers all received data patterns to

+FRM=m

none

the DTE as consecutive start-stop framed bytes, including leading marking conditions

 

 

or flags. The modem marks the end of the data stream with <DLE><ETX>.

 

 

Upon loss of carrier, the modem returns to command state and sends a ‘NO

 

 

CARRIER’ result code to the DTE.

 

 

NOTE: If the modem is on-hook, then the modem always returns an ‘ERROR’

 

 

message to the DTE after receiving the +FRM=<mod> command.

 

 

Range: <mod> = 24, 48, 72, 73, 74, 96, 97, 98, 121, 122, 145, 146

 

 

Refer to Table 23 on page 65.

 

 

 

 

 

Wait for Silence: The +FRS=<TIME> command causes the modem to send an ‘OK’

 

 

result code to the DTE when silence has been detected on the line for the amount of

 

 

time specified. The value <TIME> is in 10 ms intervals. The command terminates

+FRS=m

none

when the required amount of silence has been detected on the line or the DTE sends

 

 

the modem another character that is discarded. In either event, the DTE returns the

 

 

‘OK’ result code.

 

 

Range: <TIME> = 1–255 (10 ms)

 

 

 

NOTE: An asterisk (*) denotes the factory-default setting.

68

536EX Chipset Developer’s Manual

Intel Confidential

Page 68
Image 68
Intel 536EX Intel Confidential, Fax Class 1 AT Commands, Fax Mode Command Descriptions Continued, +FRH=m, Refer to on page