Cisco Spark Room Kit HDMI connections. Issues over 10-15ft source cable.

[chaywoo00]

Hi Everyone,

First post here, hope it's in the right section.

We have installed around 30 Cisco Spark room kits (and 2 Spark Kit+). During installation, we ran HDMI cables from the Spark Kit to the desk of the room it was in. This was sometimes a 30ft (10meter) HDMI cable for routing down walls and under floors.

When testing the Spark Kit would not recognise the signal from the laptop connected to the HDMI, it would loop on the panel with the chime noise (as though something was connected) but just keep trying to connect continually. When connecting the same cable direct to a screen-laptop, it would work with no issues at all.

If the cable from the Spark Kit to the laptop was 10-15ft (5meter) or less, it will typically work.

We have tried numerous cables of different quality and no change in results.

We have had to install Kramer Cat5/6 sender-receiver units and pull network cable in to work around it.

This is affecting all of the units we have.

Has anyone come across this issue?

Thanks,

[marwenne]

Requirements for HDMI cables (from admin guide for Codec Plus): 

HDMI cables for cameras and displays
The resolution formats larger than 1920×1200@60fps require use of high speed HDMI cables. For guaranteed operation, use HDMI cables that are pre-qualified from Cisco for use at 3840×2160@60fps, or use a cable that has passed the Premium HDMI Cable Certification Programme.
HDMI cables for presentation sources
A presentation source can be a PC/laptop, document camera, media player, whiteboard, or other device. The resolution formats larger than 1920×1080@60fps require use of high speed HDMI cables. For guaranteed operation, use a HDMI cable from Cisco, or use a cable that complies with the high speed HDMI 1.4b Category 2 specification. We recommend that you order the HDMI presentation cable from Cisco (HDMI 1.4b Category 2).

https://www.cisco.com/c/dam/en/us/td/docs/telepresence/endpoint/ce95/codec-plus-administrator-guide-ce95.pdf 

[Wayne DeNardi · Accepted solution]

Generally speaking, for high resolutions the HDMI cable should be no longer than 5m, unless it is a boosted cable.  The long content cables that come with the RoomKit devices are such cables - you will notice that they are directional as well (they only work properly when connected one way round).

For longer cable runs, then the boosted cables may not be enough, and you will, as you found, need to use other active extender options, or HDMI over Optical Fibre cables.

Whatever you do, make sure that the cable you purchase supports the bandwidth required for your application.  4K60 uses considerably more bandwidth (around 18Gbps) than 1080p (around 5Gbps).

If 9m is enough for you, and you also need different input connector options for flexibility for your end users, you could try the Cisco CAB-HDMI-MUL4K-9M= cable which was made specifically for the Cisco Room Series endpoints.