ASUS DSL-N55U

ASUS DSL-N55U (Annex A/B)

Manuf (OEM/ODM): Askey RT4070AW -D61

(Est.) release date: April 2012
Country of manuf.: China
Series: N600

Amazon image

ASIN
B007T8FO9S (, On Amazon, On CCC, multiple uses)
multiple revisions of this device, use caution

Type: wireless router, dsl modem

Power: 19 VDC, 1.58 A
Connector type: barrel

CPU1: Ralink RT3662F (500 MHz)
CPU2: TrendChip TC3162LE (450 MHz)
FLA1: 8 MiB8,388,608 B 65,536 Kib 8,192 KiB 64 Mib 0.00781 GiB  (Macronix MX29LV640EBTI-70G)
FLA2: 1 MiB1,048,576 B 8,192 Kib 1,024 KiB 8 Mib 9.765625e-4 GiB  (Winbond W25Q80BVSSIG)
RAM1: 128 MiB134,217,728 B 1,048,576 Kib 131,072 KiB 1,024 Mib 0.125 GiB  (Winbond W971GG6JB-25)
RAM2: 2 MiB2,097,152 B 16,384 Kib 2,048 KiB 16 Mib 0.00195 GiB  (Winbond W9816G6IH-6)

Expansion IFs: USB 2.0
USB ports: 2
JTAG: yes, 14-pin header
Serial: yes, 4-pin header

WI1 chip1: Ralink RT3662F
WI1 802dot11 protocols: an
WI1 MIMO config: 2x3:2
WI1 antenna connector: RP-SMA
WI2 chip1: Ralink RT3092
WI2 802dot11 protocols: bgn
WI2 MIMO config: 2x2:2
WI2 antenna connector: RP-SMA

ETH chip1: Ralink RT3662F
Switch: Realtek RTL8367R
LAN speed: 1GbE
LAN ports: 4

abgn

Stock FW OS: Linux 2.6.22.19 AsusWRT

TPFirmware supported: Bender (discontinued)

Flags: ADSL2+

Default SSID: ASUS (97 addl. devices)
, ASUS_5G (44 addl. devices)
Default IP address: 192.168.1.1
the IP 192.168.1.1 is used by 1295 additional devices
of which 167 are ASUS devices
Default login user: admin
Default login password: admin
admin:admin credentials used by 1321 additional devices
of which 198 are ASUS devices

802dot11 OUI: 14:DA:E9 (2 E, 2 W), 10:BF:48 (3 E, 4 W)
Ethernet OUI: 14:DA:E9 (2 E, 2 W), 10:BF:48 (3 E, 4 W)

	CPU1 brand	WI1 chip1 brand	WI2 chip1 brand
ASUS DSL-N55U	Ralink	Ralink	Ralink
ASUS DSL-N55U C1	MediaTek	MediaTek	Ralink

For a list of all currently documented Ralink chipsets with specifications, see Ralink.
For a list of all currently documented TrendChip chipsets with specifications, see TrendChip.

Dual-Band Wireless-N600 Gigabit ADSL Modem Router

Product page (Annex A) • Product page (Annex B)

See also: ASUS DSL-N55U C1 • Product page (Ver. C1)

Wi-Fi Certified : WFA13630 (as of 11/29/2011)

This device has two versions (same hardware components):

Annex A (A1 revision), Annex B (B1 revision)

The device has:

- Two processors, one for router part and the other for ADSL modem part;

- 8 MB flash for router part and 1 MB flash for modem part;

- 128 MB ram for router part and 2 MB ram for modem part;

- RP-SMA connectors.

- Two USB 2.0 ports, 1 Ampere max output per port.

- Capability to use a LAN port as WAN port.

Reviews

Review on ThinkBroadband

"RT4070AW-D61(RoHS)", "REV:3.0", and "Annex A" is silkscreened on the board.

Flash: Macronix MX29LV640EB (8MB)

RAM: Winbond W9816G6IH-6 (2MB)

Spec. pages

On SpeedGuide.net
On direct.it (now a dead link...) Notes specs as

Ralink RT3662 (WiSoC 5GHz 2x3:2)

Ralink RT3092 (RFIC PCIe 2.4GHz 2x2:2)

TrendChip TC3162LEM (SoC ADSL)

Realtek RTL8367R (Gigabit Switch)

Forum threads

Serial

This device is equipped with two serial ports.

The good one is near the leds and the jtag pins.

The pinout is:

      ___________________       Connection parameters:
      | VCC GND TX  RX  |       57600 8 N 1 
      |  •   •   •   •  |
      |_____|     |_____|

Firmware

The stock firmware is AsusWRT, based on Linux 2.6.22.19.

The source code is available on the device's support page:

Annex A, Annex B

• Stock firmware versions and changelogs

DSL-N55U 1.0.0.9 - First official firmware.
DSL-N55U 3.0.0.4.178
DSL-N55u 3.0.0.4.188
DSL-N55U 3.0.0.4.206 - BETA firwmare
- added "Download Master" feature, Wifi fixes
DSL-N55U 3.0.0.4.218 - BETA firmware, minor fixes
DSL-N55U 3.0.0.4.228 - BETA firmware.
- Italian is now supported.
- Fixed IPTV UDP Proxy failed to work issue.
- Fixed Wireless MAC filter issue.
- Fixed minor UI issues and compatibility issue with IE 8.
- Fixed uninstall/disable Download Master affects Media Server UI issue.
- Enable AutoFix for NTFS file system.
- Supports Stability Adjustment feature(this is the SNR tweaking that some of
requested, if you are experiencing disconnection then try to set -1dB ~ -5dB).
- Fixed reserved, upnp/ssdp, mdns mcast pass-through with 2.4GHz/5GHz band IGMP
snooping(AirPlay and AirPrint connection issue resolved).

DSL-N55U 3.0.0.4.247 - BETA firmware.
- Support SRA(Seamless Rate Adaptation) feature, enabled by default.
(Advanced Settings -> Administration -> DSL Setting)
- Now UI supports Ukrainian language.
- Fixed Internet led wrong behavior issue.
- Removed Manual Setting button while system performs Quick Internet
Setup - automatic connection type detection.
- (IPTV)Supports IGMP/UDP proxy without specific STB port configured.
- Skip scanning "Download2" and "asusware" in Media Server.
- Fixed AirPlay and AirPrint compatibility issue.
- Add PIN code error alerting for USB dongle.
- Fixed Annex B model, UI Help & Support link invalid model ID issue.

DSL-N55U 3.0.0.4.248 - BETA firmware.
- Fixed Port Trigger, Virtual Server, DMZ failed to work issue(due to related
iptables rules didn't get created).
- Add Internet Led blinking behavior when there are TX/RX traffic in WAN interface.

DSL-N55U 3.0.0.4.314
- Fixed sometimes Internet connection established, but UI shows Disconnected and Internet LED dims issue.
- Now min_free_kbytes changed from 2048K to 4096K, in order to reclaim memory earlier.
- Added QIS Mobile UI.
- USB Application 3G/4G now supports following dongles as well, specifically for Australia ISP.
Huawei K3765 (3G Vodafone), ZTE MF821 (4G Telstra), Sierra Aircard 320U (4G Telstra)
- Server-u upnp issue addressed.
- Add multicast setting in order to resolve compatibility issues with AirPrint.
Now both AirPlay/AirPrint should work fine.
- Improved time sync mechanism.
- Fixed DM link Network Map UI issue.
- Now after USB application return button is clicked, APPList will be reloaded.
- Fixed Guest Network issue.
- Support W3Networks.
- Fixed WAN link status reporting issue.

DSL-N55U 3.0.0.4.317 - BETA firmware
- Update 2.4GHz band WiFi driver.
- Supports Dual WAN(Fail-Over/Fail-Back or Load-balance),
Advanced Settings -> WAN -> Dual WAN.

DSL-N55U 3.0.0.4.335 - BETA firmware
- Now includes ADSL Uptime timer(ADSL Log page).
- ADSL Log now will refresh every 10 seconds.
- Fixed WAN -> Internet Connection, Static DNS fails to work issue.
- Fixed in Dual WAN Fail-Over mode, if Primary WAN: USB modem, and Secondary WAN: LAN(Ethernet WAN)
then Secondary WAN connection type PPPoE could not establish Internet connection issue.
- Fixed Dual WAN, Secondary WAN type cannot display properly in IE browser issue.
- Add Help messages in DSL Setting page for Stability Adjustment and SRA(Seamless Rate Adaptation).
- Add router login password strength indicator.
- Fixed possible UPnP Buffer Overflow issue.
- Fixed DDNS update issue and modify DDNS failed hint on UI.
- Add MAC Address list for Wireless MAC Filter page.
- Fixed IGMP Snooping issue with 2.4GHz band.
- Change Enable IGMP Snooping option on Wireless -> Professional page, now Disable by default.
- iTunes server: skip system directory.

DSL-N55U 3.0.0.4.364
1. Supports AiCloud (for more information, please refer to
http://event.asus.com/2012/nw/aicloud/index.htm
2. Update QIS manual setting for Germany ISP, added Vodafone, Alice/o2 and Congstar.
3. Update QIS manual setting for UK ISP BE Broadband, added BE (MER) and BE (IPoA).
4. Now includes ADSL Uptime timer (ADSL Log page).
5. Add ADSL link status icon.
6. Now supports Enable/Disable Wi-Fi of each band via UI
(that is if Hardware Wi-Fi slide switch is turned On).
7. Supports WOL (Wake-on-LAN) user interface.
8. Supports Huawei E353 3G/4G USB dongle.
9. Add router login password strength indicator.
10. Wi-Fi driver updated.
11. Add MAC Address list for Wireless MAC Filter page.
12. Add Network tools in Advanced Settings.
13. The router setting URL changed to http://router.asus.com, use the original URL
http://www.asusnetwork.net can also go to the setting page.
14. Add Help messages in DSL Setting page for Stability Adjustment and SRA
(Seamless Rate Adaptation).
15. Now click the device name could look up the manufacturer information.

Fix
1. Fixed sometimes hardware/software restore to factory default fails to take effect issue.
2. Fixed various DDNS related issues.
3. Fixed wireless time control and parental control related issues.
4. Fixed Media server related issues when LAN subnet changes or USB hot plug.
5. IPv6 over PPPoE interoperability issues addressed.
6. Fixed WAN -> Internet Connection, Static DNS fails to work issue.
7. Fixed possible UPnP Buffer Overflow issue.
8. Fixed IGMP Snooping issue with Wi-Fi 2.4GHz band.

DSL-N55U 3.0.0.5.364 - BETA firmware
- Added Dual WAN feature.

DSL-N55U 3.0.0.4.365.1 - BETA firmware
- Addressed the SendBSS2040CoexistMgmtAction spam issue.

DSL-N55U 3.0.0.4.374.158 Annex A - BETA firmware
DSL-N55U 3.0.0.4.374.159 Annex A

DSL-N55U 3.0.0.5.374.150 Annex A - BETA firmware
Added:
1. Quick Internet Setup ADSL ISP setting list updated and refined, 29 new ISP settings been added.
2. Added DSL Spectrum feature(Advanced Settings > System Log > Spectrum).
3. Added Tx power adjustment setting(Advanced Settings > Wireless > Professional).
4. Now specific Guest Network SSID can be configured whether to Enable Wireless MAC Filter or not.
5. Now supports USB HDD greater than 2TB.
6. New Parental control > Active schedule design.
7. Now supports Eject all USB disks with One-click(via UI top right USB disk icon).
8. Disk Scan feature(General > Network Map > External USB disk status > Disk Utility).
9. Added Active Connections list(Advanced Settings > System Log > Active Connections).
10. Added VPN connections status(Advanced Settings > VPN Server > VPN Status).
11. Recognized *.rmvb files as video format in Media Server.
12. Show more detail information in USB Application install process.
13. Added more options for Samba.
14. Firmware version now includes extension number.

Fixed:
1. Now Secondary 3G/4G WAN able to auto Fail-Back to Primary DSL WAN once ADSL sync up again.
2. Fixed WiFi driver SendBSS2040CoexistMgmtAction syslog spam issue.
3. Fixed after 3G/4G WAN connection established, but Internet Led still dim issue.
4. Fixed Printer Server LPR issue.
5. Reduced the redundant packets when used 3G/4G dongle as WAN and opened web browser.
6. Fixed Traffic Monitor related issues when used 3G/4G dongle as WAN.
7. Fixed Quick Internet Setup Firefox browser compatibility related issues.
8. Enhanced AiDisk Wizard setting time for enabling FTP account.
9. Fixed Sonos PLAYBAR device name caused UI JS error issue.
10. Fine tune the IO priority to make Samba higher than DM process.
11. Refine General > Network Map.
12. Fixed client duplicated issue in Network Map.
13. Fine tune Traffic Monitor.
14. Fixed IE related Parental control issue.
15. Underline(_) can now be accepted as the device name and computer name.
16. Hide Broadcast option in PPTP VPN server when it is disabled.
17. Fixed smart sync JS error.
18. Fixed JST time zone issue.
19. Fixed software reboot function when USB App installed
20. Fixed the FTP server/client file time inconsistent issue.

IPv6
1. Fixed PPP IPv6 global address retrieval.
2. Added DHCP-PD option.
3. Added LAN DHCPv6 server.
4. Added network status GUI.
5. Added option domain name if available.

3G/4G dongles:
1. Support Huawei EC306.
2. Support Yota LTE dongle LU150.
3. Support ZTE LTE dongle MF821.
4. Support 3G dongle Q110.

DSL-N55U 3.0.0.4.374.1380 Annex A - BETA firmware
- Dual WAN support officially enabled.
- Now supports Bitswap control feature, default Enabled
(Advanced Settings > Administration > DSL Setting > Bitswap)
- Allow go back to main page while during QIS ADSL auto detection/Phone line not plugged-in state.
- Stability Adjustment, now includes options -6 dB ~ -10 dB.
- QIS manual setting list updated, added Italy ISP - Fastweb (MER).
- Fixed Media Server failed to be installed issue (Our software engineer overlooked
MS v1.0.0.33 compatibility issue with firmware v3.0.0.4.374_159 and prior versions,
it will not happen again. My apologies).
- Fixed throughput issue when VPN server broadcast is enabled.
- Fixed minidlna memory leak issue.
- Fixed USB application update related issues.
- Fixed DNS Amplified DDoS vulnerability.
- Fixed Media Server related issues.
- Fixed potential security concern for Virtual Server / Port Forwarding feature.
- Fixed 2.4GHz wireless extension channel display Auto when control channel is not Auto issue.
- Fine tune Disk Utility.
- Allow access of DNS(53 port) from LAN only.
- Update USB Modem ISP list for Poland.
- Fixed Smart Sync related issues.
- Now NTP status will be reset properly.
- Fixed httpd security vulnerability.

DSL-N55U 3.0.0.4.374.1397 Annex A
1. Now supports Dual WAN feature(Advanced Settings > WAN > Dual WAN).
2. Now supports Bitswap control feature, default Enabled
(Advanced Settings > Administration > DSL Setting > Bitswap)
3. Allow go back to main page while during QIS ADSL auto detection/Phone line not plugged-in state.
4. Stability Adjustment, now includes options -6 dB ~ -10 dB.
5. QIS manual setting list updated, added Italy ISP - Fastweb (MER).
6. Fixed Media Server failed to be installed issue.
7. Fixed throughput issue when VPN server broadcast is enabled.
8. Fixed minidlna memory leak issue.
9. Fixed USB application update related issues.
10. Fixed DNS Amplified DDoS vulnerability.
11. Fixed Media Server related issues.
12. Fixed potential security concern for Virtual Server/Port Forwarding feature.
13. Fixed 2.4GHz wireless extension channel display Auto when control channel is not Auto issue.
14. Fine tune Disk Utility.
15. Allow access of DNS(53 port) from LAN only.
16. Update USB Modem ISP list for Poland.
17. Fixed Smart Sync related issues.
18. Now NTP status will be reset properly.
19. Fixed httpd security vulnerability.
20. Fixed IPTV cannot work with DSL WAN
21. Aggiunti i parametri di preconfigurazione di alcuni ISP di paesi esteri.

DSL-N55U 3.0.0.4.374_4422 Annex A
Security related issues:
1. Fixed lighthttpd vulnerability.
2. Fixed cross-site scripting vulnerability (CWE-79).
3. Fixed the authentication bypass (CWW-592).
4. Added notification to help avoid security risks.
5. Fixed network place(samba) and FTP vulnerability.
6. Modified AiDisk setup wizard to prevent a potential security issue.
7. Modified descriptions of WiFi security.

Enhancements:
1. Redesigned the parental control time setting UI.
2. Updated multi language strings.
3. Adjusted FW checking algorithm.
4. Adjusted Time zone detecting algorithm.
5. Improved web UI performance.
6. Modified MTU clamping rules.
7. Modified network map client list / UPnP replay mechanism.
8. Allowed LAN stateful settings for DHCP6.
9. Allowed manually scan after resetting.
10. Modified DMZ settings in load-balanced mode.
11. Modified virtual server settings in load balanced mode.
12. Modified some FAQ hyperlinks.
13. Modified configurations of WeTelecom WM-D300.
14. Add new Malaysia 3G ISP in USB modem.

Bug fixes:
1. Fixed wireless schedule setting issues.
2. Fixed several UI issues.
3. Fixed httpd related issues.
4. Fixed download master install issue.
5. Fixed VPN client DNS issues.
6. Fixed PPPoE throughput issues.
7. Fixed media-server related issues.

DSL-N55U 3.0.0.4.376_2734 Annex A
Network map new features:
1. System status can now show CPU and RAM usage.
2. Client icon is changeable.
3. Client name is changeable and parental control, QoS, manually assigned IP,
static route, port forwarding client list can also refer to this name.

Security related issues:
1. Fixed remote command execution vulnerability.
2. Fixed cross site scripting vulnerability.
3. Fixed parameters buffer overflow vulnerability.
4. Fixed XSS(Cross Site Scripting) vulnerability.
5. Fixed CSRF(Cross Site Request Forgery) vulnerability.
6. Added auto logout function. The timeout time can be configured in - Administration > System.
7. Included patches related to network map. Thanks for Merlin's contribution.
8. Fixed password disclosure in source code when administrator logged in.
9. Upgrade OpenSSL library from 1.0.0d to 1.0.0m.
10. Force changing FTP from anonymous to account mode after firmware upgraded.

Enhancements:
1. Supports Country-Specific Setting (Advanced Settings > Administration > DSL Setting).
2. Fine tune Stability Adjustment options (Advanced Settings > Administration > DSL Setting).
3. Spectrum feature now located at Traffic Manager > Spectrum.

Bug fix:
1. Fixed 3G/ 4G dongle compatibility issues for some Huawei dongles.
2. Fixed secondary wan setting issues in dual wan fail over mode.
3. Fixed traffic monitor display issues.
4. Daylight saving time can be manually adjusted.
5. Fixed IPTV related issues.
6. Fixed Parental control check box UI issues.
7. Dual wan fail over now support fail back.
8. Fixed wake on lan magic packet sending issue.
9. Fixed IPv6 related issues.
10. Fixed IE and Firefox compatibility issues.
11. Network map will show notification when newer firmware available.
12. Fixed USB tray icon UI bug.

DSL-N55U 3.0.0.4.376_2736 Annex A
- Fixed infosvr security issue.
- Fixed Cross-site request forgery security issue.

DSL-N55U 9.0.0.4.380_3925 Annex A - BETA firmware
Security Fixed
- Enhanced the login authentication strength and fixed CSRF related issues.
- Fixed multiple security issues

Enhancement:
- Added IPv6 Passthrough support.
- Added QoS Bandwidth limiter support.
- Added Google Domain/SELFHOST.DE and removed TZO DDNS service.
- Improved NetworkMap.
- Added reboot schedular.

Thanks to Hardware Upgrade (italian forum thread)

Web UI hidden pages

- LAN Switch control: http://192.168.1.1/Advanced_SwitchCtrl_Content.asp

• Changelog

Until firmware 3.0.0.4.374_1397 options are:
- Jumbo frame (12 KB)
- GRO (not working)
- HW acceleration (not working)

Since firmware 3.0.0.4.374_4422 options are:
- Jumbo frame (12 KB)
- NAT acceleration (not working)

Since firmware 9.0.0.4.380_3925 options are:
- Jumbo frame (12 KB)
- NAT acceleration (not working)

- Operation Mode: http://192.168.1.1/Advanced_OperationMode_Content.asp

Doens't work

- Command Console: http://192.168.1.1/Main_AdmStatus_Content.asp

Since firmware 3.0.0.4.374_4422 it does not work anymore.

Hidden features

Available via telnet console. Not sure if they are all working properly.

- Downstream output power value, relative capacity occupation and carrier load:

cat /tmp/adsl/tc_bits_per_carrier.txt

• Sample output

admin@DSL-N55U:/tmp/home/root# cat /tmp/adsl/tc_bits_per_carrier.txt

relative capacity occupation: 100%
noise margin upstream: 9.5 db
output power downstream: 19.3 dbm
attenuation upstream: 8.0 db
carrier load: number of bits per symbol(tone)
tone   0- 31: 00 00 00 57 9a ab bc dd cd dc cd dc cb ba 98 76
tone  32- 63: 56 68 9a ac cd de ff ff ff ff ff ff ff ff ff ff
tone  64- 95: ff ff ff f2 ff ff ff ff ee ee fe ff ef ff ef fe
tone  96-127: ee ee ee ef ff ee ee ee ee ee ee ee ee ee ee ee
tone 128-159: ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee ee
tone 160-191: ee ed de de dd dd dd ee dd de dd ed dd dd dd dd
tone 192-223: dd dd dd dd dd dd dd dd dd dd dd dd dd dd dd dd
tone 224-255: dd cd dd cd dd dd cd dd dd dd dd dd dd dd dd dd
tone 256-287: dd dd dd dd dd cc dc dd dd dd dd dd cc cc cc cc
tone 288-319: cc cc cc cc cc cc cc cc bc cb bb bb bb bb bb bb
tone 320-351: bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb bb
tone 352-383: bb bb ba bb bb ba aa bb bb bb ba ba ab ba aa aa
tone 384-415: aa 99 aa aa aa ab ab ab b9 aa aa aa a9 9a aa aa
tone 416-447: aa ab aa aa 99 99 a9 9a 9a aa aa 99 99 a9 a9 99
tone 448-479: 99 99 98 98 88 89 99 89 88 89 88 88 88 88 88 88
tone 480-511: 88 98 88 88 78 77 78 77 77 87 77 77 77 77 77 77

• "No such file or directory" issue fix
Generate the graphs in the "Spectrum" tab in the setup page, then retype the command.

- SNR table: cat /tmp/adsl/tc_snr.txt

• Sample output

admin@DSL-N55U:/tmp/home/root# cat /tmp/adsl/tc_snr.txt
 18.20  21.42  21.42  27.96  30.58  33.53  34.00  39.55 %  32~ 39
 39.76  42.43  42.43  45.58  48.91  48.45  48.66  48.91 %  40~ 47
 48.45  48.91  48.66  48.66  48.45  48.91  48.66  48.45 %  48~ 55
 48.91  48.66  48.91  48.45  48.66  48.66  48.45  48.91 %  56~ 63
 48.91  49.16  48.91  48.66  48.91  48.66  48.45  47.55 %  64~ 71
 48.66  48.45  48.91  48.66  48.19  48.91  48.66  48.66 %  72~ 79
 45.78  45.78  45.78  45.78  48.66  45.58  48.91  48.66 %  80~ 87
 46.04  48.66  48.66  48.45  45.78  48.66  48.19  45.78 %  88~ 95
 45.78  46.04  45.58  45.58  46.04  45.78  45.58  48.91 %  96~103
 48.19  47.94  45.58  45.78  45.78  45.58  45.78  45.78 % 104~111
 45.58  45.58  45.32  45.58  45.58  45.78  46.04  45.32 % 112~119
 45.58  45.58  45.32  45.78  45.78  46.04  45.78  45.58 % 120~127
 45.78  45.58  45.58  45.58  46.29  45.58  46.04  45.58 % 128~135
 45.58  45.78  45.32  45.78  45.78  45.78  45.78  45.58 % 136~143
 45.78  46.04  45.58  46.04  45.78  45.78  46.04  46.04 % 144~151
 45.78  46.04  45.78  45.32  45.58  45.58  45.58  45.32 % 152~159
 45.32  45.32  45.32  42.64  42.64  45.58  42.43  45.32 % 160~167
 42.43  42.43  42.64  42.64  42.64  42.89  45.32  45.07 % 168~175
 42.43  42.43  42.64  45.32  42.43  42.89  45.58  42.43 % 176~183
 42.64  42.64  42.43  42.89  42.43  42.43  42.64  42.43 % 184~191
 42.43  42.89  42.43  42.89  42.43  42.17  42.43  42.17 % 192~199
 42.43  42.64  42.43  42.64  42.43  42.43  42.64  42.43 % 200~207
 42.43  42.43  42.17  42.64  42.64  42.43  42.17  42.64 % 208~215
 42.43  42.89  42.64  42.64  42.43  42.43  42.64  42.43 % 216~223
 42.43  42.43  39.76  42.43  41.92  42.17  39.29  42.17 % 224~231
 42.89  42.43  42.43  42.43  39.76  42.43  42.64  42.17 % 232~239
 42.43  42.64  42.64  42.64  42.17  42.43  42.17  42.64 % 240~247
 42.64  42.89  42.17  42.43  42.43  42.64  42.43  42.43 % 248~255
 42.89  42.64  42.64  42.43  42.43  42.64  43.14  42.17 % 256~263
 42.64  42.43  39.76  39.29  42.43  40.02  42.43  42.64 % 264~271
 42.43  42.64  42.17  42.64  42.64  42.17  42.17  42.64 % 272~279
 39.76  39.55  39.76  39.55  39.55  39.55  39.76  39.76 % 280~287
 39.76  39.55  39.55  39.76  39.55  39.55  39.55  39.55 % 288~295
 39.29  39.55  39.29  39.76  40.02  39.55  39.05  39.55 % 296~303
 36.61  39.29  39.05  36.41  36.61  36.61  36.61  36.61 % 304~311
 36.87  36.41  36.61  36.61  36.61  36.41  36.87  36.41 % 312~319
 36.41  36.41  36.41  36.14  36.61  36.41  36.61  36.41 % 320~327
 36.61  36.41  36.41  36.87  36.87  36.41  36.87  36.41 % 328~335
 36.61  36.61  36.41  36.41  36.87  36.14  36.14  36.41 % 336~343
 36.41  36.41  36.41  36.14  36.14  36.41  36.61  36.41 % 344~351
 36.61  36.87  36.14  36.14  36.14  33.27  36.61  36.61 % 352~359
 36.41  36.14  36.61  33.53  34.24  33.74  36.41  36.61 % 360~367
 35.90  36.41  36.41  35.90  36.41  33.27  36.41  33.27 % 368~375
 33.27  36.14  35.90  33.03  33.03  33.27  33.03  33.03 % 376~383
 33.03  33.03  30.58  31.33  33.03  33.03  33.03  32.76 % 384~391
 33.03  32.76  33.27  35.90  33.27  35.90  33.27  35.90 % 392~399
 36.14  30.58  33.53  33.27  32.76  33.03  33.53  33.27 % 400~407
 33.53  31.33  31.09  33.53  33.03  33.27  33.03  33.03 % 408~415
 33.03  33.03  33.03  35.90  33.27  33.03  33.27  33.03 % 416~423
 30.38  30.38  30.12  30.58  33.03  30.38  30.12  32.76 % 424~431
 30.38  33.27  32.76  33.03  33.03  33.03  30.12  30.12 % 432~439
 30.38  30.38  33.03  30.58  33.03  30.38  30.38  30.38 % 440~447
 30.38  30.38  30.38  30.38  30.58  27.96  30.58  28.21 % 448~455
 27.96  27.50  27.71  30.12  30.38  30.38  27.71  30.12 % 456~463
 27.71  27.50  27.96  30.12  27.50  27.50  27.71  27.50 % 464~471
 27.50  27.50  27.23  27.71  27.71  27.50  27.50  27.96 % 472~479
 27.71  27.71  29.87  27.71  28.21  27.96  27.96  27.71 % 480~487
 24.33  27.50  24.33  23.83  24.33  27.71  24.33  24.33 % 488~495
 24.33  24.33  27.50  24.07  24.33  24.33  24.33  24.33 % 496~503
 24.33  24.07  24.07  24.33  24.80  24.33  24.33  24.33 % 504~511

• "No such file or directory" issue fix
Generate the graphs in the "Spectrum" tab in the setup page, then retype the command.

• Enhanced sudden noise protection

'''- Enhanced sudden noise protection:''' 
:<code>nvram set dslx_adsl_esnp=''value''</code>

Admitted values:
* 0 (disabled) [Default]
* 1 (enabled)

'''- Dynamic line adjustment (DLA):'''
:<code>nvram set dslx_dla_enable=''value''</code>

Admitted values:
* 0 (disabled)
* 1 (enabled) [Default]

'''- ADSL RX auto gain control (AGC):''' 
:<code>nvram set dslx_adsl_rx_agc=''value''</code>

Admitted values:
* Default [Default]
* Stable
* High Performance

'''- G.INP (impulse noise protection):''' 
:<code>nvram set dslx_ginp=''value''</code>

Admitted values:
* 0 (disabled) [Default]
* 1 (enabled)

For futher informations about this features visit ASUS DSL Settings FAQ

Custom firmware

There is a project of a custom firmware (AsusWRT-Bender) based on AsusWRT-Merlin custom firmware:

https://github.com/matteocrippa/dsl-n55u-bender - Original development by Matteo Crippa, now discontinued;
https://github.com/IceMans/dsl-n55u-bender - Development by IceMans, now discontinued.

Images

Asus Images

angled1
back
angled2
PCB Ports
Rear Ports
Power Supply

Wikidevi Images

board top, HS on
PCB rev 3.0
main component
RTL8367R closeup
board bottom
underside