Perhaps before you continue to make schoolboy silly comments about my posts, which seems to be something you like doing, you should look more closely at the exchange leading up to the post you smart-assedly criticise.

In this case you will see I was merely pointing out that partial has no idea of the contract that was drawn up, and I gave two possibilities. With one of them he would be right, with the other he would be wrong.

By contrast, you are just a PITA.

When did I get you so upset? What did I do to you? It clearly hurt.

Just drop it will you please. You annoy me in the same way as a housefly in the room does - no effect on my life at all. Just an insect causing a distraction to my train of thought.

I don't kill flies these days. I just guide them out. They seem much happier once I save them from banging their heads against the window. You could learn something from houseflies.

Edit - typo.

Edited by RobertoS (Tue 06-Mar-12 23:47:59)

I think if If it was me I would get myself a 1500mA psu and use that.

http://cpc.farnell.com/jsp/level5/module.jsp?moduleI...

There is a 12v 2A one

Edited by deleted (Wed 07-Mar-12 07:21:03)

ThinkBroadband contributor MHC has already performed some useful tests on the Huawei HG612. MHC discovered that the Huawei draws a peak current of 550mA on a 40/10Mbps 17MHz VDSL2 service. [1]

His findings closely correlate with the specs published in the latest release (Feb 2012) of the BT Supplier Info Note (SIN 498 Issue 3.3) [2]

According to British Telecom, the power consumption of the Huawei HG612 ("Type 1 VDSL2 Active NTE") is <6.5W.

6.5W = 540mA @ 12V.

As an aside, the other VDSL2 CPE, the ECI B-FOCuS V-2FUb/I Rev.B ("Type 2 VDSL2 Active NTE") consumes <8.6W.

The EU issued Regulations (EC Regs 1275/2008) on the power consumption of broadband access equipment. The Code of Practice to those Regulations defines target efficiency levels for broadband CPE. Manufacturers are expected to meet those targets.

For our interest - establishing the demands of the PSU of the HG612 - we need to know the full power operational state of the modem, rather than its power consumption in "standby" or "low-power" modes.

The Huawei HG612 is powered by a Broadcom 6368 System-on-Chip (SoC). The 6368 is highly integrated and requires few external components with their own load. The 6368 integrates a dual-MIPS32 core, an analog front end (AFE) and a line driver, and a number of 'chiplet' modules. [3]

The Huawei is based upon the Broadcom 96368MVWG board reference design. Several of the 6368 core modules are not used by the Huawei. These modules include a USB host controller and a SLAC controller for analog voice telephony. The 6368 also supports an external 802.11n transceiver but this is not present on the Huawei. To reduce power consumption, unused modules are disabled by the Huawei at boot-time.

Broadcom has published a White Paper entitled "BCM63XX/BCM68XX Power Management" in satisfaction of those EC regulations [4] Several board reference designs are listed with their power consumptions in various states.

The 96368MVNGR [VDSL2, 4FE, 802.11n (43222), USB] is the closest reference design to the 96368MVWG design used by Huawei for the HG612.

According to Broadcom, the 96368MVNGR consumes 7.3 watts in Full-Power state. However, that figure includes the power consumption of an active 802.11n radio and USB host controller, neither of which are used by the Huawei. 7.3 watts must be well in excess of the maximum power consumption of the Huawei...

7.3W = 610mA @ 12V.

According to those back-of-envelope calculations, the original 700mA rated PSU supplied with the HG612 is quite capable of adequately powering the device safely.

cheers, a

[1] http://forums.thinkbroadband.com/fibre/4098966-power...
[2] http://www.sinet.bt.com/498v3p3a.pdf
[3] http://pdf.eccn.com/pdfs/Datasheets/Broadcom/CM6368.pdf
[4] http://www.broadcom.com/collateral/wp/63XX_68XX-WP10...

Edited by deleted (Wed 07-Mar-12 23:45:42)

Brilliant .

Facts!

I wonder why the bigger PSU is specified for new modems? Might it need more power on 80/20? Were MHC's tests on 8c or 17a?

My tests were on 17MHz profile capped at 40Mbps downstream with comments about increases to 80/20 and further downstream changes to a 30MHz profile.

As Asbokid says, the Broadcom figures correlate with the Huawei consumption but there are some components missing, but it probably does not account for the Ethernet ports.

As I said the old supply would cope - but may be towards it's limit. With too many years of electronics design behind me, I would be considering something a little greater than 700mA - just one of those feelings that comes with experience.

Suit yourself, but as they are not expensive I would go for a larger capacity psu.

Its not a problem I will face, FTTC has not graced these parts yet.

Here's another from satcure at less than a tenner

http://www.satcure.co.uk/accs/page5.htm

Edited by deleted (Wed 07-Mar-12 19:10:43)

In reply to a post by MHC:

just one of those feelings that comes with experience.

Yes, I agree.

A safety margin as narrow as that for a device intended to run continuously and (largely) unattended cannot be considered to be a safe design.

The original 700mA black PSU for the Huawei sells for just 75 pence in China. [1] BT purchased the units in six-figure volumes, and probably paid less than half that. Maybe I'm just stingy but £16 is a lot to charge for a 'wall wart', whatever its rating.

Has anyone examined the construction and performance of switched-mode PSUs? This one (the 700mA rated FM120007-UK) has been heat-sealed and cannot easily be opened for examination.

How noisy are these PSUs? According to Alcatel-Lucent, the switching converters of SM-PSUs are "known to be a common source of EMI for in-house cabling networks that carry DSL signals. The DSL performance can degrade substantially because of such interference" [2]

An interesting project there for an EE student!

cheers, a

[1] http://item.taobao.com/item.htm?id=14687748456
[2] http://www.wipo.int/patentscope/search/docservicepdf...

Edited by deleted (Wed 07-Mar-12 20:09:08)

BT has said no need to swap PSU, and stated PSU is perfectly good for the job. Perhaps time for people to wait and see if there are failures and enjoy suitable gloating time.

In reply to a post by MrSaffron:

BT has said no need to swap PSU, and stated PSU is perfectly good for the job.

They have indeed... what was it they said about reports of overheating modems in the early days?