Technical Discussion
  >> DSL Hardware Discussion


Register (or login) on our website and you will not see this ad.


  Print Thread
Standard User Bobby_Valentino
(fountain of knowledge) Wed 15-May-13 16:05:08
Print Post

HG612 FTTC Modem


[link to this post]
 
Hi

What speeds does this modem support from the RJ11 that comes in from the BT master socket...in other words what frequency of VDSL does the modem support 17a, 30a?

TIA.

My Broadband Speed Test
Standard User BatBoy
(legend) Wed 15-May-13 19:02:17
Print Post

Re: HG612 FTTC Modem


[re: Bobby_Valentino] [link to this post]
 
Openreach FTTC is 17a. The modem can handle 30a.


__________________________________________________________________________The back pedalling starts here__________________
Standard User asbokid
(member) Fri 17-May-13 01:33:01
Print Post

Re: HG612 FTTC Modem


[re: Bobby_Valentino] [link to this post]
 
The Broadcom BCM6368 is the embedded processor powering the HG612 and a good many other VDSL2 CPE.

The processor reportedly supports Profile 30a, yet we cannot get the device to sync on Profile 30a. We tested with a 30MHz Huawei H835VDGE linecard. It has a Broadcom BCM6516 dual chipset.

The DSL layer of the CPE repeatedly tries to auto-negotiate down to Profile 17a. When the MA5616 DSLAM with V800R310 firmware is configured to disable that downwards auto-negotiation, the CPE won't sync at all.

One of the other Openreach VDSL2 CPE is the ECI vg3503j. It is known also as the /r revision model. By contrast, that ECI device does sync with a Profile 30a line profile.

Though even with a zero loop (a loop of effectively zero length), the outcome is not that impressive. With the IP profile removed, the line sync rate is still only ~105Mbps up and ~115Mbps down. Not to be sneezed at, but nowhere near the 200Mbps theoretical maximum!

That experiment was using a PSD class mask of AnnexB998ADE30-M2x-NUS0-A (B8-16) which is the nearest 30MHz equivalent to the AnnexB998ADE17-M2x-A (B8-11) mask used by BT Openreach for its Profile 17a service.

cheers, a

P.S. For those interested, here is the line operation data when the ECI /r is synced on Profile 30a:

Text
1
23
45
67
89
1011
1213
1415
1617
1819
2021
2223
2425
2627
2829
3031
3233
3435
3637
3839
4041
4243
4445
4647
4849
5051
52
MA5616(config-if-vdsl-0/3)#display line operation 0
  ------------------------------------------------------------------------------  Standard in port training                  : G.993.2-Annex B
  Current power management state             : Full-on state  Result of the last full initialization     : Communication fail
  G.998.4 retransmission used downstream     : Unused, retransmission mode is forbidden  G.998.4 retransmission used upstream       : Unused, retransmission mode is forbidden
  Signal attenuation downstream(dB)          : 15.6  Signal attenuation upstream(dB)            : 0.0
  Line attenuation downstream(dB)            : 15.6  Line attenuation upstream(dB)              : 0.0
  Maximum attainable rate downstream(Kbps)   : 100014  Maximum attainable rate upstream(Kbps)     : 108708
  Actual line rate downstream(Kbps)          : 116560  Actual line rate upstream(Kbps)            : 105192
  Line SNR margin downstream(dB)             : 25.4  Line SNR margin upstream(dB)               : 8.8
  Actual PSD downstream(dBm/Hz)              : -  Actual PSD upstream(dBm/Hz)                : -
  Actual KL0_CO value(0.1dB)                 : 0  Actual KL0_CPE value(0.1dB)                : 0
  Total output power downstream(dBm)         : 12.0  Total output power upstream(dBm)           : 7.2
  Current VDSL2 profile                      : Profile30a  Coding gain in downstream(dB)              : -
  Coding gain in upstream(dB)                : -  Power cut back downstream(dB)              : -
  DS1 band:      Signal attenuation(dB)                 : 15.6
      Line attenuation(dB)                   : 15.6      Line SNR margin(dB)                    : 25.9
  US1 band:      Signal attenuation(dB)                 : 0.0
      Line attenuation(dB)                   : 0.0      Line SNR margin(dB)                    : 8.9
  DS2 band:      Signal attenuation(dB)                 : 8.9
      Line attenuation(dB)                   : 8.8      Line SNR margin(dB)                    : 25.9
  US2 band:      Signal attenuation(dB)                 : 0.0
      Line attenuation(dB)                   : 0.0      Line SNR margin(dB)                    : 8.8
  DS3 band:      Signal attenuation(dB)                 : 0.2
      Line attenuation(dB)                   : 0.2      Line SNR margin(dB)                    : 25.2
  US3 band:      Signal attenuation(dB)                 : 1.4
      Line attenuation(dB)                   : 0.3      Line SNR margin(dB)                    : 8.8
  ------------------------------------------------------------------------------

Edited by asbokid (Fri 17-May-13 02:36:41)


Register (or login) on our website and you will not see this ad.

  Print Thread

Jump to