Cisco 7975G Software Guide

DNS or Other Connectivity Errors
Problem
The phone reset continues and you suspect DNS or other connectivity issues.
Solution
If the phone continues to reset, eliminate DNS or other connectivity errors with Determine DNS or Connectivity
Issues, on page 231.
Power Connection Problems
Problem
The phone does not appear to be powered up.
Solution
In most cases, a phone restarts if it powers up by using external power but loses that connection and switches
to PoE. Similarly, a phone may restart if it powers up by using PoE and then connects to an external power
supply.
Cisco Unified IP Phone Security Problems
The following sections provide troubleshooting information for the security features on the Cisco Unified IP
Phone. For information about the solutions for any of these issues, and for additional troubleshooting
information about security, see Cisco Unified Communications Manager Security Guide.
CTL File Problems
The following sections assist in troubleshooting CTL file problems.
Authentication Error, Phone Cannot Authenticate CTL File
Problem
A device authentication error occurs.
Cause
CTL file does not have a Cisco Unified Communications Manager certificate or has an incorrect certificate.
Solution
Install a correct certificate.
Cisco Unified IP Phone 7975G, 7971G-GE, 7970G, 7965G, and 7945G Administration Guide for Cisco Unified
Communications Manager 9.0 (SCCP and SIP)
222
Troubleshooting and Maintenance
Cisco Unified IP Phone Security Problems

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