Cisco Systems ATA187I1ARF manual Troubleshooting and Maintenance General Troubleshooting Tips

Chapter 6 Troubleshooting and Maintenance

General Troubleshooting Tips

Table 6-2	ATA 187 Troubleshooting (continued)
Summary		Explanation
Prolonged broadcast storms		A prolonged Layer 2 broadcast storm (lasting several minutes) on
cause phones to reset, or be		the voice VLAN may cause phones to reset, lose an active call, or
unable to make or answer a call		be unable to initiate or answer a call. Phones may not come up until
		a broadcast storm ends.
Moving a network connection		If you are powering your phone through the network connection,
from the phone to a workstation		you must be careful if you decide to unplug the phone’s network
		connection and plug the cable into a desktop computer.
		Caution The computer’s network card cannot receive power
			through the network connection; if power comes through
			the connection, the network card can be destroyed. To
			protect a network card, wait 10 seconds or longer after
			unplugging the cable from the phone before plugging it
			into a computer. This delay gives the switch enough time
			to recognize that there is no longer a phone on the line
			and to stop providing power to the cable.
Changing the phone		By default, the network configuration options are locked to prevent
configuration		users from making changes that could impact their network
		connectivity. You must unlock the network configuration options
		before you can configure them.
Dual-Tone Multi-Frequency		When you are on a call that requires keypad input, if you press the
(DTMF) delay		keys too quickly, some of them might not be recognized.
Codec mismatch between the		The RxType and the TxType statistics show the codec that is being
phone and another device		used for a conversation between this ATA 187 and the other device.
		The values of these statistics should match. If they do not, verify
		that the other device can handle the codec conversation or that a
		transcoder is in place to handle the service.
Sound sample mismatch		The RxSize and the TxSize statistics show the size of the voice
between the phone and another		packets that are being used in a conversation between this ATA 187
device		and the other device. The values of these statistics should match.
Gaps in voice calls		Check the AvgJtr and the MaxJtr statistics. A large variance
		between these statistics might indicate a problem with jitter on the
		network or periodic high rates of network activity.

Cisco Unified IP Phone Administration Guide for Cisco Unified Communications Manager 8.0

6-8 OL-21035-01