Cisco 7975G Troubleshooting And Maintenance

Step 5 From Cisco Unified Communications Manager, choose Device > Phone and verify that you have assigned
the correct MAC address to this Cisco Unified IP Phone. For information about determining a MAC address,
see Cisco Unified IP Phone MAC Address Determination.
Step 6 Power cycle the phone.
General Troubleshooting Information
The following table provides general troubleshooting information for the Cisco Unified IP Phone.
Table 2: Cisco Unified IP Phone Troubleshooting
ExplanationSummary
Cisco does not support connecting an IP phone to
another IP phone through the PC port. Each IP phone
should directly connect to a switch port. If phones are
connected together in a line (by using the PC port),
the phones do not work.
Daisy-chaining IP phones
In Cisco Unified Communications Manager, you can
configure the network to use the G.729 protocol (the
default is G.711). When using G.729, calls between
an IP phone and a mobile phone will have poor voice
quality. Use G.729 only when absolutely necessary.
Poor quality when calling mobile phones using the
G.729 protocol
A prolonged Layer 2 broadcast storm (lasting several
minutes) on the voice VLAN may cause IP phones to
reset, lose an active call, or be unable to initiate or
answer a call. Phones may not come up until a
broadcast storm ends.
Prolonged broadcast storms cause IP phones to reset,
or be unable to make or answer a call
If you are powering your phone through the network
connection, you must be careful if you decide to
unplug the phone network connection and plug the
cable into a desktop computer.
The computer 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 no phone is on the line and
to stop providing power to the cable.
Caution
Moving a network connection from the phone to a
workstation
Troubleshooting and Maintenance
16
Troubleshooting and Maintenance
General Troubleshooting Information

Cisco 7975G Specifications

General

Handset type	Wired handset
Product type	IP Phone
Product color	Grey, Silver
Speakerphone	Yes
Voice codecs	G.711Mu, G.711a, G.722, G.729A, iLBC
Number of melodies	24
Aspect ratio	4:3
Display diagonal	5.6 \
Display resolution	320 x 240 pixels
Lines quantity	8 lines
Phonebook capacity	- entries
Number of VoIP accounts	-
Front camera	No
Security algorithms	128-bit AES
Networking standards	IEEE 802.1Q, IEEE 802.1p, IEEE 802.1x, IEEE 802.3af
Ethernet LAN data rates	10, 100, 1000 Mbit/s
Ethernet LAN interface type	Gigabit Ethernet
Supported network protocols	DHCP, TFTP
Volume control	Digital
Headphone outputs	1
Ethernet LAN (RJ-45) ports	2
Number of handles included	1 pc(s)
AC adapter output voltage	48 V
Storage temperature (T-T)	-10 - 60 °C
Operating temperature (T-T)	0 - 40 °C
Operating relative humidity (H-H)	10 - 95 %
Certification	FCC

Weight and Dimensions

Depth	152.4 mm
Width	266.7 mm
Height	203.2 mm
Weight	1600 g