Cisco OL-20949-01 - Manual (Page 60)

5-12
Cisco Unified IP Phone Services Application Development Notes
OL-20949-01
Chapter 5 Internal URI Features
Multimedia URIs
Play
The Play URI downloads an audio file from the TFTP server and plays through the phone speaker. This
same mechanism also plays ring files, and the format of the files is the same. You could use the Play URI
to play files that are in the Ringlist.xml or those that are not. If the phone is equipped with an MWI light,
it will be flashing while the audio file is playing, providing a visual alert as well.
Note The Play URI is a synchronous request. If the request is pushed to the phone via HTTP, the HTTP
response (CiscoIPPhoneResponse object) is not returned until after the playback has completed.
Interaction with Incoming Calls
The Play URI and incoming calls (ringing) have equal priority access to the DSP ringer resources
resulting in the following interactions:
• If a Play URI is currently playing, an incoming call (ringing) will not preempt the Play URI; the
Play URI will finish playing first.
• If the phone is ringing and a Play URI request is sent to the phone, the execution of the Play URI
defers until the phone stops ringing (the DSP ringer resource becomes available) and then the Play
URI will play.
URI Format
Play:f
Where
f = the filename of a raw audio file in the TFTP path (such as Play:Classic2.raw).
The audio files for the rings must meet the following requirements for proper playback on Cisco Unified
IP Phones:
• Raw PCM (no header)
• 8000 samples per second
• 8 bits per sample
• uLaw compression
• Maximum ring size—16080 samples
• Minimum ring size—240 samples
• Number of samples in the ring is evenly divisible by 240.
• Ring starts and ends at the zero crossing.
To create PCM files for custom phone rings, you can use any standard audio editing packages that
support these file format requirements.
Vibrate
The Vibrate URI is available on the Cisco Unified IP Phones 7920G, 7921G, and 7925G wireless phone
models, and it enables third-party applications to invoke the phone’s vibration capabilities for silent
alerts, similar to the way in which the Play URI plays audible alerts. If the Vibrate parameters are not
specified or if the device is unable to support custom Vibrate sequences, the device will execute its
default vibrate sequence.