Intel 537EX manual Intel Confidential, Data Mode AT COMMANDS, 536EX Chipset Developer’s Manual

Data Mode AT COMMANDS

Figure 5. Modem-on-Hold: Initiating a Voice Call in Data Mode

Enable MOH

(+PMH=0)

Command Mode

(+++AT)

Request to go

on hold

(+PMHR)

Server

Accepts No (Returns 0)

Request

?

Yes (Returns 1-13)

Flash Hook

(+PMHF)

Initiate Call

Finish Call

Flash Hook

(+PMHF)

Disconnect	No
?

Yes

End Data Connection

(ATH)

Go Back Online

(ATO)

A9112-01

The following sequence describes how to configure the modem for MOH to process an incoming voice call while online. First, MOH must be enabled. The +PMH and +PCW commands are used to enable MOH and to capture the Call Waiting tone which is sent when the voice call comes in. To enable MOH, set +PMH=0 and +PCW=0. Next, to enable Caller ID information (optional), by setting +VCID=1. Now the modem is configured for the incoming call. When you receive the incoming call, the modem will get a ring indication and the software/application will issue a

+++AT to put the modem in command mode. Then, you will be prompted to either “Accept” or “Reject” the call based on the Caller ID information (if enabled). If you reject the call, an ATO command is issued to perform a Quick Connect to stay online. If you accept the call, the data connection is put on hold, and the modem send a request to the server to go on hold using the +PMHR command. The server will accept enable (1–13 returned) or reject (0 returned) the request. If the server accepts the request to go on hold, the modem issues the +PMHF to flash the

536EX Chipset Developer’s Manual 33

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