External design and hardware

Firmware upgrade and add-ons


Command line




For quite a long time our testing laboratory hadn’t got an ADSL-switch at our disposal which didn’t give us a possibility to test ADSL routers. That’s why when we obtained DSLAM D-Link DAS-3248EC, we made up our minds to not limit our tests with this vendor’s devices only, but we also asked some other companies for their ADSL-modem. That’s how we got an ASUS DSL-N12U wireless router in our lab, and here’s its review below.

External design and hardware

An ASUS DSL-N12U wireless ADSL-router is designed in a black case made of shiny plastic with a grey horizontal panel and dimensions of 179x119x37 mm (excluding the external antennas). For its work the device requires an external power source with the following characteristics: 12V and 1.5A.

On the front panel there is the model name engraved and some LEDs indicating status of the device and its ports: four for the LAN ports, one for Wi-Fi, an ADSL light indicates the connection with the provider’s equipment (if it doesn’t work, the further adjustment is of no use), and Internet shows the connection to the provider in the mode PPPoA/PPPoE.

The side panels are quite featureless: there is a grey plastic panel as well and some small holes for ventilation.

The upper panel is shiny and there’s a 3D brand tag on it. The lion’s share of this panel is occupied with a vent.

Most part of the device bottom is occupied by the vent and more than that, there is a sticker with some brief information about the model, four rubber stands and two T-shaped technological holes which allow placing the DSL-N12U both on the table and on the wall.

On the rear panel there are two non-detachable external antennas with the amplifying factor of 5dBi. Also one can find here four Fast Ethernet ports, one port for connecting the phone line, one USB 2.0 interface, the on/off button, the wireless module Power button and two small round buttons to reset the user’s settings and to simplify connection of new wireless devices.

Now let’s have a look inside the device. All the electronic stuffing is presented by one green textolite board which main elements are located on one side.

The whole system is based on the SoC chip from the Ralink company. Only three chips are not covered: the Winbond W9816G6IH flash-drive with the capacity of 2Mbyte, the TrendChip TC3162LE-LQ128G CPU and the TrendChip TC3086-QFN64-EPG module which is responsible for working with ADSL.

Let’s turn to the software review of the router.

Firmware upgrade and add-ons

The procedure of firmware upgrade in ASUS DSL-N12U is similar to those models that are suitable for the most of the wireless devices from this vendor – you just need to select the file with a new firmware in the point “Firmware upgrade” in the group “Administration” and press the button “Upload”.

The entire process takes approximately three minutes and doesn’t require any special skills from the user. The firmware version is displayed in the point “Firmware upgrade” of the “Administration group” and on the main page of the router itself.

If some malfunction occurs while firmware is being updated, ASUS DSL-N12U enters the rescue mode characterized by the power LED slow blinking. It should be mentioned that the user can manually turn on this mode of the router by switching on the device with the Reset button and holding it during ten seconds. Some minor features pointing out the rescue mode of DSL-N12U can be the lack of echo-replies of the protocol ICMP and the fact that its MAC-address becomes equal to 4040.4040.4040.

Pinging with 32 bytes of data:
Request timed out.
Request timed out.
Request timed out.
Request timed out.
Ping statistics for
Packets: Sent = 4, Received = 0, Lost = 4 (100% loss),
Interface: --- 0x36
Internet Address Physical Address Type 40-40-40-40-40-40 dynamic

To restore the firmware it’s necessary to use the ASUS Firmware Restoration utility which is a part of the software set for this very model. The restoration procedure is quite simple: you need to choose the file with the firmware needed and click the button “Upload”, all the rest will be accomplished by the utility itself.

You can restore the firmware manually, without using any special utilities. It is required to change the IP-address from which the recovery is going to take place. You can find it out with the help of traffic capturing via the Wireshark or TCPdump utilities, generated by the device into the LAN-segment. In our case, ASUS DSL-N12U regularly sent the APR-requests about the address, that’s why we used exactly this value for our IP-address of the testing host. After changing the IP-address it’s necessary to send the file with the required firmware to the device with the help of the TFTP protocol and wait for the device to reboot. All the commands are shown below.

C:\>tftp -i put c:\DSL-N12U_1.0.3.7.trx
Successful transfer: 4348652 bytes in 4 s, 1087163 bytes/s
C:\>ping -t
Pinging with 32 bytes of data:
Request timed out.
Request timed out.
Reply from bytes=32 time=2000ms TTL=64
Reply from bytes=32 time<1ms TTL=64
Reply from bytes=32 time<1ms TTL=64

Besides the above-mentioned utility there are also three more ones in the software set for DSL-N12U: Printer Setup, ADSL Setting Wizard and Device Discovery that allow a user/an administrator to install on the stationary PC a printer connected to the router USB port, to configure all the settings of the router for it to work with a certain provider and to detect DSL-N12U in the local segment of the network.

Scrutinizing the abilities of each utility is beyond this review, so let’s just turn to the review of the device web-interface.


To access the web- interface of the wireless ADSL-router any modern browser can be used. The IP-address of the LAN-interface is by default, the login is admin.

Having logged in all the necessary data, the user gets on the start page of the device from which s/he can pass over to the Internet connection Wizard or to the page for configuration of all the preferable traffic types. The ASUS DSL-N12U web-interface is available in 14 languages.

We would like to mention that more fine adjustments of the services quality are available in the tab “QoS” of the group “WAN”.

Moreover, from the start page the user can go straight to the device advance mode. We are not going to look into all the settings, but mention some of the most interesting ones.

The tab “Professional” in the group “Wireless network” depicts the current state of the module and allows switching it on/off according to the schedule. Also there are some other wireless network fine adjustments available here.

The items “LAN IP-address” and “DHCP-server” of the group “LAN” give an opportunity to not only change the IP-address of the LAN-interface and manage the operating parameters of the DHCP-server, but also to turn on/off the translation of the net addresses (NAT/PAT). This procedure is completed by choosing the working mode of the router. Quite a pleasant option of the DHCP-server turned out to be a possibility to point out the gateway IP-address manually.

Not only do the sub-items “DSL WAN”, “Ethernet WAN” and “3G WAN” of the “WAN” group allow setting the ADSL-port of the router, but also choosing one of the LAN-interfaces as an Internet link. ASUS DSL-N12U can be connected not only to the ADSL and Ethernet providers but also to 3G networks.

With the help of the tab “IPTV” of the same group the administrator can specify the device ports which set top boxes are connected to. Some other multicast settings are gathered in here.

The filter parameters on the basis of URL and MAC addresses can be changed in the tabs of the group “Firewall”. Also it’s possible to get the access to some definite global resources according to the schedule.

The tabs of the group “Administration” allow changing the administrator’s password and the parameters of time synchronization, upgrading firmware and managing the user’s settings. You can find the ADSL-port fine adjustments here too.

The “Log” group provides the administrator with the access to the log information of the system, DHCP-server, wireless and ADSL modules. Besides this here you can see the routing table and port forwarding table. To one of this group’s minor drawbacks we would like to include the excessively wide Russian titles of the tabs.

That is the end of our web-interface review of the ASUS DSL-N12U wireless ADSL-router. Let’s switch to learning the functions of the device command line.

Command line

To access the command line via the Telnet protocol it’s necessary to log in using the same password as to access the router web-interface. The operating system of the ASUS DSL-N12U wireless router is Linux version 2.6.21 and BusyBox version 1.12.1.

DSL-N12U login: admin
BusyBox v1.12.1 (2012-05-30 04:29:58 GMT) built-in shell (ash)
Enter 'help' for a list of built-in commands.
# busybox
BusyBox v1.12.1 (2012-05-30 04:29:58 GMT) multi-call binary
Copyright (C) 1998-2008 Erik Andersen, Rob Landley, Denys Vlasenko
and others. Licensed under GPLv2.
See source distribution for full notice.
Usage: busybox [function] [arguments]...
or: function [arguments]...
BusyBox is a multi-call binary that combines many common Unix
utilities into a single executable. Most people will create a
link to busybox for each function they wish to use and BusyBox
will act like whatever it was invoked as!
Currently defined functions:
[, [[, arp, ash, basename, brctl, cat, chmod, chpasswd, cp, date,
dd, echo, expr, free, ftpget, ftpput, grep, hostname, ifconfig,
insmod, kill, killall, klogd, ln, logger, login, logread, ls, lsmod,
mdev, mkdir, mknod, mount, mv, netstat, nslookup, ping, ps, pwd,
rm, rmmod, route, sed, sh, sleep, syslogd, telnetd, test, tftp,
top, touch, traceroute, umount, vconfig, vi, wc, zcip
# cat /proc/version
Linux version 2.6.21 (asus@localhost) (gcc version 3.4.2) #1826 Wed May 30 12:38:35 CST 2012

Using the command ps let’s see what processes are running at the moment. The top utility will display the data on the current work of these processes.

# ps
1 admin 2700 S /init
2 admin 0 SWN [ksoftirqd/0]
3 admin 0 SW< [events/0]
4 admin 0 SW< [khelper]
5 admin 0 SW< [kthread]
30 admin 0 SW< [kblockd/0]
33 admin 0 SW< [khubd]
45 admin 0 SW< [kswapd0]
46 admin 0 SW [pdflush]
47 admin 0 SW [pdflush]
48 admin 0 SW< [aio/0]
182 admin 0 SW [mtdblockd]
263 admin 0 SW< [dwc_otg]
285 admin 0 SW [RtmpWscTask]
316 admin 1552 S tp_init
318 admin 1732 S /sbin/syslogd -m 0 -t UTC-4 -O /tmp/syslog.log
320 admin 1732 S /sbin/klogd
322 admin 3152 S httpd eth2.1
326 admin 1780 S /usr/sbin/infosvr br0
327 admin 1116 S /usr/sbin/udhcpd /tmp/udhcpd.conf
329 admin 1204 S dnsmasq -C /tmp/dnsmasq.conf
331 admin 1568 S lpd
332 admin 2376 S u2ec
333 admin 2376 S u2ec
334 admin 2692 S usdsvr_broadcast
335 admin 2692 S usdsvr_unicast
337 admin 2376 S u2ec
340 admin 1196 S lld2d br0
341 admin 1468 S /usr/sbin/wanduck
347 admin 2268 S /usr/sbin/pppd file /tmp/ppp/options.wan0
358 admin 1452 S internet_led
360 admin 0 Z [failover_monito]
362 admin 0 Z [failover_3g]
363 admin 2692 S watchdog
376 admin 2692 S ntp
379 admin 2692 S ots
391 admin 1736 R telnetd
392 admin 1788 S networkmap
393 admin 1740 S /bin/sh
450 admin 1748 S -sh
485 admin 1736 R ps
Mem: 22276K used, 6376K free, 0K shrd, 0K buff, 12824K cached
CPU: 0% usr 8% sys 0% nice 91% idle 0% io 0% irq 0% softirq
Load average: 0.00 0.01 0.00
492 450 admin R 1740 6% 8% top
322 1 admin S 3152 11% 0% httpd eth2.1
1 0 admin S 2700 9% 0% /init
363 1 admin S 2692 9% 0% watchdog
376 1 admin S 2692 9% 0% ntp
379 1 admin S 2692 9% 0% ots
334 1 admin S 2692 9% 0% usdsvr_broadcast
335 1 admin S 2692 9% 0% usdsvr_unicast
333 332 admin S 2376 8% 0% u2ec
332 1 admin S 2376 8% 0% u2ec
337 333 admin S 2376 8% 0% u2ec
347 1 admin S 2268 8% 0% /usr/sbin/pppd file /tmp/ppp/options.w
392 1 admin S 1788 6% 0% networkmap
326 1 admin S 1780 6% 0% /usr/sbin/infosvr br0
450 391 admin S 1748 6% 0% -sh
393 1 admin S 1740 6% 0% /bin/sh
391 1 admin S 1736 6% 0% telnetd
318 1 admin S 1732 6% 0% /sbin/syslogd -m 0 -t UTC-4 -O /tmp/sy
320 1 admin S 1732 6% 0% /sbin/klogd
331 1 admin S 1568 5% 0% lpd
316 1 admin S 1552 5% 0% tp_init

Let’s find out what files are located in the catalogues /bin, /sbin, /usr/bin and /usr/sbin.

# ls /bin
chmod gpio sdparm ated
cp lld2d ls flash
umount rm grep iptables-restore
mii_mgr busybox wscd dnsmasq
rt2860apd kill iwconfig iwpriv
ash ping switch sleep
mkdir touch mount spicmd
dd igmpproxy ez-ipupdate tc
login usb_modeswitch sed sh
cat iptables hostname
mv echo pwd reg
ln mtd_write vi
mknod upnpd comgt
ps date netstat
# ls /sbin
gen_ralink_config halt
lsmod start_ddns
wan-up ATE_Get_MacAddr_2G
start_telnetd start3g
sta_wps_stop run_ftp
getSiteSurvey ATE_Get_ResetButtonStatus
wps_pin ATE_Get_PINCode rc
ip-down FWRITE
vconfig start_ots
erase hotplug_usb_mass
test_of_var_files_in_mount_path get_device_id
ATE_Set_PINCode gbe
disktest asuscfe
wps_start restart_dns
getChannel ATE_Set_RegulationDomain
switch_to_3gwan write_smb_conf
setCountryCode radioctrl
getBSSID getBootV
ATE_Set_PowerLedOn getPIN
tracktest wps_oob setBootV
auth-down apcli_monitor
nvram_restore zcip
gbr ejusb getIMG
auth-up apcli_connect
gpio_setbit ATE_Get_RegulationDomain getSSID run_apps
ddns_updated reboot
wmac switch_to_dslwan
start_ntp setMAC
insmod getStaConnectionSSID
setPIN init
hotplug run_upnp
watchdog stop_ftp
convert_asus_values get_sw
ifconfig rsrom
route ATE_Get_BootLoaderVersion
get_modem_node ATE_Get_WpsButtonStatus
stop3g ip-up
ledoff ATE_Set_RestoreDefault
wan-down ping_keep_alive
apcli_set gpio_wrint
rmmod gpio_rdint
usdsvr_unicast gpiotest
chg_to_ethwan sigmon
logmessage restore
write ATE_Get_SWMode
wsrom ATE_Set_PowerLedOff
pspfix getApCliInfo
ots startWan
ATE_Get_WlanButtonStatus sta_wps_pbc klogd
initial_var_file send_sms
dhcpc_apply_delayed setDisassociate
ATE_Get_FWVersion getMAC
ateshow spiread
wps_pbc speedtest
umount2 getCurrentAddress
read_sms getCountryCode
ATE_Set_MacAddr_2G wphy
ATE_Set_StartATEMode ntp
ledon syslogd
ATE_Get_Usb2p0_Port1_Infor getWPSAP
mdev eject_usb1
chkalltask stopservice
wps_stop arp logread
# ls /usr/bin
test nslookup ftpget expr free
killall traceroute ftpput [ basename
top tftp logger wc [[
# ls /usr/sbin
arpstorm internet_led udhcpd failover_monitor
pppd tp_init ntpclient spiflash
infosvr telnetd pppoe-relay chpasswd
networkmap nvram l2tp-control u2ec
lpd adslate udhcpc l2tpd
brctl wanduck udpxy failover_3g
httpd bpalogin auto_det

Now let’s move to the catalogue /proc and have a look at the files we can find here and learn the uptime of the operating system and its average load, and get the information about the installed CPU and the RAM capacity.

# cd /proc/
# ls
527 337 263 loadavg interrupts sys
450 335 182 uptime slabinfo irq
393 334 48 meminfo buddyinfo misc
392 333 47 version vmstat scsi
391 332 46 filesystems zoneinfo ioports
379 331 45 cmdline diskstats iomem
376 329 33 locks modules timer_list
363 327 30 execdomains kcore kallsyms
362 326 5 mounts net swaps
360 322 4 kmsg sysvipc crypto
358 320 3 devices fs mtd
347 318 2 cpuinfo driver rt2880
341 316 1 partitions tty Config
340 285 self stat bus spiflash
# cat uptime
1335.37 1316.40
# cat loadavg
0.00 0.00 0.00 3/41 530
# cat cpuinfo
system type : Ralink SoC
processor : 0
cpu model : MIPS 24K V4.12
BogoMIPS : 255.48
wait instruction : yes
microsecond timers : yes
tlb_entries : 32
extra interrupt vector : yes
hardware watchpoint : yes
ASEs implemented : mips16 dsp
VCED exceptions : not available
VCEI exceptions : not available
# cat meminfo
MemTotal: 28652 kB
MemFree: 6320 kB
Buffers: 0 kB
Cached: 12828 kB
SwapCached: 0 kB
Active: 7280 kB
Inactive: 7752 kB
SwapTotal: 0 kB
SwapFree: 0 kB
Dirty: 0 kB
Writeback: 0 kB
AnonPages: 2244 kB
Mapped: 1688 kB
Slab: 4344 kB
SReclaimable: 952 kB
SUnreclaim: 3392 kB
PageTables: 392 kB
NFS_Unstable: 0 kB
Bounce: 0 kB
CommitLimit: 14324 kB
Committed_AS: 5652 kB
VmallocTotal: 1048404 kB
VmallocUsed: 2188 kB
VmallocChunk: 1045676 kB

We can’t help mentioning the nvram utility which allows changing the important parameters of the device.

# nvram
usage: nvram [get name] [set name=value] [unset name] [show]
# nvram show | grep pass
size: 17698 bytes (15070 left)

This brings us to the end of the device command line interface review of the ASUS DSL-N12U wireless ADSL-router and pass over to the testing section.


The first test which we always start this section with is estimation of the device booting time under which we mean the time interval between switching the power on and receiving the first echo reply via ICMP. ASUS DSL-N12U boots within 27 seconds and we find it a good result.

Our second usual test is to check the security of the device via the Positive Technologies XSpider 7.7 (Demo build 3100) security scanner. On the whole there were twelve open ports detected: TCP-23 (Telnet), TCP-53 (DNS), UDP-53 (DNS), TCP-80 (HTTP), TCP-515 (printer), TCP-3394 (d2k-tapesty2), TCP-3838 (Unavailable), TCP-5473 (unknown), TCP-9100 (Unavailable), TCP-9998 (Unavailable), TCP-18017 (HTTP) and TCP-49152 (HTTP). The most significant information is shown below.

Now it’s time for the most long-wanted tests of our readers – the device performance tests. In the table below we display all the main parameters of our testing stand.

Component PC Notebook
Motherboard ASUS Maximus V Extreme ASUS M60J
CPU Intel Core i7 3770K 3.5 GHz Intel Core i7 720QM 1.6 GHz
RAM DDR3 PC3-10700 SEC 32 Gbyte DDR3 PC3-10700 Kingston 8 Gbyte
NIC Intel Gigabit CT Desktop Adapter
Atheros AR8131
Atheros AR9285
Operating system Windows 7 x64 SP1 Rus Windows 7 x64 SP1 Rus

We started with the estimation of the maximum speed of user data transmission through the wireless segment.

The speeds we got here correspond to the wireless segment performance which means that both wired and wireless networks in DSL-N12U are balanced.

We decided to not limit ourselves with measuring only the maximum speeds that are available in the router, but to check its work in various ADSL-modes.

Since ASUS DSL-N12U gives you an opportunity to not only connect to ADSL, but also to Ethernet-providers as well, we made up our minds to find out the speeds which could be available to the user in the following modes: routing and NAT, PPTP tunnel without encrypting and with MPPE128 encrypting.

We finish the testing section now and pass over to a conclusion.


All in all we are satisfied with the ASUS DSL-N12U ADSL-router and a possibility to organize backup connections with the help of wireless USB-modems or Ethernet-providers doubles its attractiveness for ADSL Internet connection.

The good points are listed below.

  • External antennas with the amplification gain of 5dB
  • Internet connection possibility not only via ADSL, but also using the Ethernet and 3G providers
  • Annex M support
  • Possibility to switch on/off the wireless module manually and according to the schedule
  • Good data transmission speeds through the Ethernet-providers connection

Unfortunately, we can’t miss the drawbacks of the tested model.

  • Excessive size of the device web-interface
  • It's impossible to connect external disks or flash-drives to USB.

At the moment of writing this article the average price of the ASUS DSL-N12U ADSL-router in Moscow online stores was 2000 rubles.

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