User`s manual

AT Command Reference Manual
3-54 1048
Example 2:
Switch from normal handset conversation to AudioSpan data connection between two RCV288 modems. The
originate DTE is set to 57600 bps and the answer DTE is set to 115200 bps:
Originate Modem Answer Modem
DTE DCE DTE DCE Comments
Users establish handset
conversation and both handsets
are off-hook.
AT&F AT&F Reset modems.
OK OK
AT-SMS=2 AT-SMS=2 Enable AudioSpan with default
settings. Modems are aware
handsets are already being used
due to line current sensing.
OK OK
ATD Originate modem initiates data
negotiation but will not actually
dial since the handset is already
offhook.
RING Answer modem detects
negotiation sequence and reports
RING message to DTE.
ATA DTE responds to RING by
answering.
CONNECT 57600 CONNECT 115200 AudioSpan is established and
user’s can resume conversation.
The connect message represents
the DTE speed on each side.
<data> <data> Modems exchange data.
+++ Answer modem enters command
mode to prepare for disconnect.
OK
ATH
NO CARRIER NO CARRIER Modems disconnect in AudioSpan
mode but handsets are still
offhook and conversation can
continue. Conversation is
terminated when both handsets
are hung up.
Note:
The transition from handset conversation to AudioSpan mode can take up to 8 seconds. The handsets will be silenced
during the negotiation period.