Changing The Built-In Modem Operating Mode - Ericsson T39 At Command Reference

3.3 Changing the built-in modem operating mode

The following illustration summarises the methods that are used to switch between the three built-in modem
operating modes:
3.3.1 Operating in off-line command mode
Lose carrier
or
lose I.R. link
or
press "No"
button
(or pull DTR
low ) or ATH
*
Pull DTR not available
*
when using cable.
In off-line command mode, the built-in modem accepts data as commands and not as normal communication
traffic. You enter commands by typing at the PC/PDA keyboard.
Switching to on-line data mode
To enter on-line data mode, for data to be exchanged with the modem at the other end of the link, enter the
ATD command followed by the telephone number to make the call. Alternatively, typing ATA to answer an
incoming call will also place the built-in modem in on-line mode.
Switching back to off-line command mode
Any of the following will return the built-in modem to off-line command mode from on-line data mode:
• Loss of the connection (NO CARRIER error)
• Loss of the infrared link between the built-in modem and your computer
• Pressing the "NO" button on your mobile phone
Off-line Command Mode
Exchange AT command data between computer and
Built-in Modem
Dial
Answer
ATD
ATA
<tel.no.>
On-line Data Mode
Exchange data or facsimile
with a remote modem
+++AT <?>
(or pull DTR
low
*)
On-line Command Mode
Exchange AT command data with the Built-in
Modem while staying on-line
Power up
Lose carrier
or
lose I.R.
link
or
press "NO"
button
(or
pull DTR
low
*)
ATO
AT Commands 10