Longshine LCS-8056C2 - Manual (Page 115)

Commands for Host-Processed Modems Reference Manual
100498E Conexant 4-5
If no more data is in the transmit buffer, and the last transmitted character was not an ASCII
NULL, the modem generates the OK result code and returns to the command mode. If the last
character transmitted was an ASCII NULL, the modem generates the CONNECT message to
the DTE and waits for further data from the DTE while transmitting NULLs to the remote. If
more data is received before five seconds elapse, the modem continues to transmit the data as
described in the previous paragraph. If five seconds elapse and no data is received from the
DTE, the modem drops carrier, goes on-hook, and generates the ERROR result code.
4.1.9 Fax Data Reception
Fax data reception is initiated using the AT+FRM=<mod> command. After this command is
issued, the modem looks for carrier in the modulation scheme specified by the parameter n. If
no carrier is detected before the period of time specified by register S7 expires, the modem
generates the NO CARRIER message and returns to command mode. If a V.21 carrier is
detected when a high speed carrier is expected, the modem generates the +FCERROR
message and returns to the command mode. If the specified carrier is detected, the modem
generates the CONNECT message and enters the data receive mode.
While in data receive mode, the modem receives data from the remote, adds start and stop
bits, and handles <DLE><chr> character pairs before passing the data to the DTE. The
modem prefixes each <DLE> character with another <DLE> character before sending it to the
DTE.
If the modem detects a receive buffer overflow condition, it stops receiving from the remote
until there is room in the receive buffer. The modem informs the DTE of the buffer overflow
after it sends to the DTE the last character that was stored in the buffer before the overflow
occurred.
If the modem receives any character from the DTE after the +FRM command (except flow
control characters if software flow control is in effect), or if the modem detects a high-to-low
transition of the DTR signal while &D1 is in effect, it sends <DLE><ETX> to the DTE,
generates the OK result code, and returns to command mode. The receive buffer is cleared
and all data received from the remote is discarded. If loss of DTR is detected while &D2 is in
effect, the modem goes on-hook, sends <DLE><ETX> followed by OK result code to the
DTE, and returns to command mode. If the modem detects a DTR drop while &D3 is in
effect, the modem performs a warm reset.