Cisco 7970 pantalla borrosa

[c.salcedo]

Buen dia,

Tengo varios Cisco IP phone 7970 en switches Cisco POE 2960X y 2960 720W de 48ports...pero se ve la pantalla borrosa... si conecto esos telefono a otro Switch POE pero de los tipo SMB o Linksys ahi si se ve bien....imagino que debe ser algo del voltaje pero la verdad no lo se.... a alguien le ha pasado esto?

[Leonardo Pena Davila]

Hola efectivamente este problema viene dado por la cantidad de voltaje que suministra el puerto del switch al telefono. Adjunto tambla que pueda ser util:

Phone Power Consumption and Display Brightness

The power consumed by a phone depends on its power configuration. See Table 2-1 for a power configuration overview. See Table 2-2 for the maximum power consumed by a phone for each configuration option and the correlating phone screen brightness level.

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Note Power consumption values shown in the table include power losses in the cable that connects the phone to the switch.

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Table 2-2 Power Consumption and Display Brightness for Power Configurations 

Phone Model	Power Configuration	Max. Power Consumed from a Switch	Phone Screen Brightness
Cisco Unified IP Phone 7970G	Cisco prestandard inline power from a switch that supports a maximum of 7 W power per port, with bidirectional power negotiation enabled	6.3 W	Approx. 1/2
	Cisco prestandard inline power from a Cisco Switch that supports 7 W or 15.4 W power per port, without bidirectional power negotiation	6.3 W	Approx. 1/2
	IEEE 802.3af Class 3 power from a Cisco switch, without bidirectional power negotiation	6.3 W	Approx. 1/2
	IEEE 802.3af Class 3 power from a third-party switch	6.3 W	Approx. 1/2
	IEEE 802.3af Class 3 power from a Cisco switch, with bidirectional power negotiation enabled	10.25 W	Full1
	Cisco prestandard inline power from a Cisco Switch that supports 15.4 W power per port, with bidirectional power negotiation enabled	10.25 W	Full
	External power using the CP-PWR-CUBE-3 power supply	—	Full
Cisco Unified IP Phone 7971G-GE	IEEE 802.3af Class 3 power from a Cisco switch (with or without bidirectional power negotiation enabled) or from a third-party switch	15.4 W	Near full
	External power CP-PWR-CUBE-3 power supply	—	Full

¹Starts at approximately 1/2 brightness, changes to full brightness when the phone negotiates additional power.

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Note When a phone is powered with a method that does not support full brightness for the phone screen, the phone Brightness control (Settings > User Preferences > Brightness) will not allow you to set the brightness to the maximum value.

[c.salcedo]

Gracias por responder Leonardo,

Pero no entiendo....si tengo switches cisco 720W supuestamente deberia trabajar sin problemas, mas por que tengo otros que si funcionan sin problemas, lo que me confunde es que al conectarlo a un POE Linksys ahi si funciona.....por eso imaginaba que pudiese ser el voltaje, no encuentro en que parte de la configuracion del telefono pueda ver esto....ya que otros telefonos conectados al mismo switch funcionan, llevo estos otros que no funcionan a los mismos puertos y no funcionan.....pero en el linksys si.....esto esta muy raro.