User Tools

Site Tools


toh:mikrotik:rb493g
The Wiki is getting migrated to a new server, edits are disabled until further notice.

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revision Previous revision
Previous revision
toh:mikrotik:rb493g [2012/12/25 16:32]
toh:mikrotik:rb493g [2016/02/02 20:30] (current)
danitool [Tags]
Line 1: Line 1:
 +====== Mikrotik Routerboard RB493G ======
  
 +===== Hardware Highlights =====
 +^ CPU                          ^ Ram      ^ Flash                        ^ Network ​        ^ USB                ^ Serial ​         ^ JTag                    ^ MiniPCI ​         ^
 +| Atheros AR7161 680/800 MHz   | 256MiB ​  | 128MiB, 1x Micro-SD-socket ​  | 9x 1000Base-T ​  | 1x 2.0 unpowered ​  | Yes (console) ​  | ??? (contacts on PCB)   | 3x Type IIIA/​B ​  |
 +
 +==== Pricing/​Where to buy ====
 +^ Shop                      ^ Country ​  ^ Routerboard 493G   ^ Encasing CA493   ^ Last checked ​  ^
 +| http://​shop.meconet.de/ ​  | DE        | 140,- €            | 19,- €           | 2012-12-25 ​    |
 +| http://​varia-store.com/ ​  | DE        | 172,- €            | 20,- €           | 2012-12-25 ​    |
 +| http://​varia-store.com/ ​  | DE        | 220,- $            | 26,- $           | 2012-12-25 ​    |
 +
 +===== Installation =====
 +
 +==== Flash Layout ====
 +Please check out the article [[doc:​techref:​Flash.Layout]]. It contains an example and a couple of explanations.
 +<​code>​root@OpenWrt:/#​ cat /proc/mtd
 +dev:    size   ​erasesize ​ name
 +mtd0: 0000b000 00001000 "​routerboot"​
 +mtd1: 00001000 00001000 "​hard_config"​
 +mtd2: 00002000 00001000 "​bios"​
 +mtd3: 00001000 00001000 "​soft_config"​
 +mtd4: 00040000 00020000 "​booter"​
 +mtd5: 003c0000 00020000 "​kernel"​
 +mtd6: 07c00000 00020000 "​rootfs"</​code>​
 +The two partitions used to install OpenWrt are kernel and rootfs. Their sizes are in bytes with hex, which translates to 3840KiB for kernel and 126976KiB for rootfs.
 +
 +==== Netboot via BOOTP/TFTP ====
 +
 +The bootloader is able to load an image in ELF-format via BOOTP/DHCP and TFTP into RAM and execute it.
 +
 +=== Use another OpenWrt router as netboot server ===
 +
 +This is the easiest way to achieve a live boot of your RB493G, but it requires that you already have an OpenWrt router with net-access available. You will need to obtain an elf-image for the RB493G, and make it available to the other router. If you have enough memory available on the other router, you can put the image on the /tmp folder there, e.g., like this:
 +<​code>​ssh root@192.168.1.1
 +wget --directory-prefix=/​tmp http://​downloads.openwrt.org/​attitude_adjustment/​12.09-beta2/​ar71xx/​nand/​openwrt-ar71xx-nand-vmlinux-initramfs.elf</​code>​
 +Now enable dnsmasq'​s built in tftp server, and point it to the correct locations, e.g., like this:
 +{{ media:​mikrotik:​tftpnetbootconfig.png?​630 |Setting up netboot in Luci, note the full path for the filename. }}
 +That's it, Save and apply, connect the Eth1/WAN port of RB493G to one of the other routers LAN ports, and continue to [[toh:​mikrotik:​rb493g#​setup_the_routerboard|Setup the Routerboard]].
 +
 +Make sure you asigned a static lease for the MAC address of the Routerboards eth1 port, otherwise bootp wont work.
 +
 +=== Use a Debian based server for netboot ===
 +
 +You need a BOOTP- and a TFTP-server on your host-machine,​ we use ''​dnsmasq''​ here, since it can provide both services. Install dnsmasq with:
 +<​code>​sudo apt-get install dnsmasq</​code>​
 +
 +Note that network-manager has a dependency on dnsmasq-base,​ which will block port 53. Hence, you may need to remove dnsmasq-base,​ e.g., with
 +<​code>​sudo aptitude install dnsmasq dnsmasq-base-</​code>​
 +you may need to reinstall dependencies that will be removed in the process.
 +ref. http://​ubuntuforums.org/​showthread.php?​p=12006425
 +
 +Changes in /​etc/​dnsmasq.conf:​
 +
 +  - make sure the LAN has internet access: <​code>​ping openwrt.org</​code>​
 +  - only listen on the interface which is directly connected to the same LAN like the WAN-port (Eth1/PoE) of the RouterBoard via a layer2 switch, e.g. <​code>​interface=eth0</​code>​
 +  - set default gateway, e.g. <​code>​dhcp-option=option:​router,​192.168.177.1</​code>​
 +  - allow a DHCP range which is within netmask of your LAN but does not conflict with other DHCP-service,​ e.g. <​code>​dhcp-range=192.168.177.2,​192.168.177.5,​2m</​code>​
 +  - allocate an IP address to the board, e.g. <​code>​dhcp-host=00:​0C:​42:​XX:​XX:​XX,​192.168.177.2</​code>​ (replace the XX with the MAC address of your board!)
 +  - enable dnsmasq'​s built-in TFTP-server <​code>​enable-tftp</​code>​
 +  - set the root directory-for files available via TFTP. <​code>​tftp-root=/​srv/​tftp</​code>​
 +  - download initramfs-kernel-image into root-directory of the TFTP-server:​ <​code>​wget --directory-prefix=/​srv/​tftp http://​downloads.openwrt.org/​attitude_adjustment/​12.09-beta2/​ar71xx/​nand/​openwrt-ar71xx-nand-vmlinux-initramfs.elf</​code>​
 +  - set filename of kernel image for tftp-server/​BOOTP:<​code>​dhcp-boot=/​srv/​tftp/​openwrt-ar71xx-nand-vmlinux-initramfs.elf</​code>​
 +
 +Finally restart dnsmasq
 +<​code>​sudo /​etc/​init.d/​dnsmasq restart</​code>​
 +
 +=== Setup the Routerboard ===
 +
 +  - Connect to the serial port with a null modem cable (115200, 8N1, no handshaking).
 +  - Press a key shortly after powering the board.
 +  - Press **o** to change the boot device
 +  - Press **1** to boot from ethernet once.
 +  - Press **x** to leave setup (-o-1-x is needed only once, the boot method is saved in non-volatile memory)
 +
 +If everything is setup correctly it should look like:
 +
 +<​code>​
 +\0x00
 +
 +RouterBOOT booter 2.29
 +
 +RouterBoard 493G
 +
 +CPU frequency: 680 MHz
 +  Memory size: 256 MB
 +
 +Press any key within 2 seconds to enter setup..
 +writing settings to flash... OK
 +trying bootp protocol... OK
 +Got IP address: 192.168.177.2
 +resolved mac address 00:​14:​0B:​3F:​BB:​C3
 +Gateway: 192.168.177.1
 +transfer started ............................... transfer ok, time=1.46s
 +setting up elf image... OK
 +jumping to kernel code
 +[    0.000000] Linux version 3.3.8 (renne@renne) (gcc version 4.6.3 20120201 (prerelease) (Linaro GCC 4.6-2012.02) ) #1 Mon Sep 17 12:57:18 CEST 2012
 +[    0.000000] bootconsole [early0] enabled
 +[    0.000000] CPU revision is: 00019374 (MIPS 24Kc)
 +[    0.000000] SoC: Atheros AR7161 rev 2
 +[    0.000000] Clocks: CPU:​680.000MHz,​ DDR:​340.000MHz,​ AHB:​170.000MHz,​ Ref:​40.000MHz
 +[    0.000000] Determined physical RAM map:
 +[    0.000000] ​ memory: 08000000 @ 00000000 (usable)
 +[    0.000000] User-defined physical RAM map:
 +[    0.000000] ​ memory: 10000000 @ 00000000 (usable)
 +[    0.000000] Initrd not found or empty - disabling initrd
 +[    0.000000] Zone PFN ranges:
 +[    0.000000] ​  ​Normal ​  ​0x00000000 -> 0x00010000
 +[    0.000000] Movable zone start PFN for each node
 +[    0.000000] Early memory PFN ranges
 +[    0.000000] ​    0: 0x00000000 -> 0x00010000
 +
 +...
 +
 +Please press Enter to activate this console. [   ​21.710000] device eth0 entered promiscuous mode
 +[   ​21.720000] device eth1.1 entered promiscuous mode
 +[   ​21.720000] device eth1 entered promiscuous mode
 +[   ​23.110000] eth0: link up (1000Mbps/​Full duplex)
 +[   ​23.130000] br-lan: port 1(eth0) entered forwarding state
 +[   ​23.130000] br-lan: port 1(eth0) entered forwarding state
 +[   ​23.600000] eth1: link up (1000Mbps/​Full duplex)
 +[   ​23.610000] br-lan: port 2(eth1.1) entered forwarding state
 +[   ​23.620000] br-lan: port 2(eth1.1) entered forwarding state
 +[   ​25.130000] br-lan: port 1(eth0) entered forwarding state
 +[   ​25.620000] br-lan: port 2(eth1.1) entered forwarding state
 +</​code>​
 +
 +Press **Enter** and you are in the console of OpenWRT running from RAM and booted via BOOTP/TFTP.
 +
 +Note that you may need to set dns servers to get net-access while running the netbooted image. Enter a working dns for you in
 +<​code>​vi /​tmp/​resolv.conf.auto</​code>​
 +then restart dnsmasq to make the change effective (cross-check that you indeed have net-access afterwords):​
 +<​code>/​etc/​init.d/​dnsmasq restart</​code>​
 +
 +==== Permanent Installation ====
 +
 +You need a working **Netboot** first, see above.
 +
 +=== Erase the NAND Flash ===
 +
 +If you want to install OpenWrt permanently into the NAND flash you once need to erase the NAND flash to get rid of the RouterOS stuff:
 +
 +  - connect via serial line
 +  - press a key shortly after powering the RB493G up
 +  - press **e** and type **yes** to format the flash from the bootloader
 +  - power off the Routerboard
 +
 +=== Install OpenWrt into Flash ===
 +
 +  - Start **Netboot** (see above).
 +  - Press ENTER to get a shell prompt.
 +  - Execute:
 +<​code>​
 +wget2nand http://​downloads.openwrt.org/​attitude_adjustment/​12.09/​ar71xx/​nand/​
 +</​code>​
 +
 +You can adjust the path-part dependend on the OpenWRT-version ('​attitude_adjustment/​12.09'​),​ but make sure you use the '​ar71xx/​nand/'​-branch and at least version '​12.09-rc2'​.
 +
 +==== Upgrading OpenWrt ====
 +
 +Use the **Permanent-Installation**-Guide via **BOOTP/​TFTP-Netboot** from above.
 +
 +==== An installation experience ====
 +=== Providing tftp boot and images with an existing openwrt router ===
 +== On the existing openwrt router ==
 +File ''/​etc/​config/​dhcp''​
 +<​file>​
 +config dnsmasq
 +        ...
 +        option '​enable_tftp'​ '​1'​
 +        option '​tftp_root'​ '/​tmp/​tftpboot/'​
 +
 +config '​boot'​ '​pxe_mikrotik_rb493g'​
 +        option '​filename'​ '​vmlinux'​
 +        option '​servername'​ '​routersetup'​
 +        option '​serveraddress'​ '​192.168.88.254'​
 +
 +config '​host'​ '​mikrotik'​
 +        option '​name' ​  '​mikrotik'​
 +        option '​mac' ​   '<​the ip address of the eth1 port on the mikrotik>​ You can find it from the mikrotik winbox interface'​
 +        option '​ip' ​    '​192.168.88.1'​
 +
 +config dhcp '​lan'​
 +        option interface '​lanmikrotik'​
 +        option start '​10'​
 +        option limit '​150'​
 +        option leasetime '​10m'​
 +
 +...
 +</​file>​
 +
 +File ''/​etc/​config/​network''​
 +<​file>​
 +...
 +
 +config interface '​lan'​
 +        option type '​bridge'​
 +        option ifname '​eth0.0'​
 +        option proto '​static'​
 +        option ipaddr '​192.168.1.254'​
 +        option netmask '​255.255.255.0'​
 +
 +config interface '​lanmikrotik'​
 +        option ifname '​br-lan'​ #it is an alias interface
 +        option proto '​static'​
 +        option ipaddr '​192.168.88.254'​
 +        option netmask '​255.255.255.0'​
 +        ​
 +...
 +</​file>​
 +
 +We need to provide files. Therefore:
 +<​file>​
 +cd /tmp/
 +mkdir tftpboot
 +wget '​http://​downloads.openwrt.org/​attitude_adjustment/​12.09-beta2/​ar71xx/​nand/​openwrt-ar71xx-nand-vmlinux-initramfs.elf'​
 +#this image is needed for booting from the ram
 +
 +ln -s openwrt-ar71xx-nand-vmlinux-initramfs.elf vmlinux
 +# to match the bootloader requests
 +</​file>​
 +
 +  * Connect the eth1 port of the mikrotik to the lan ports of the openwrt router.
 +  * Unplug the power cable of the mikrotik.
 +  * With the proper tool press the button (o reset button) near to the eth1 interface on the mikrotik and hold it (continue reading).
 +  * Plug the mikrotik power cable.
 +  * Wait for the boot of the mikrotik (careful, if the mikrotik has a license level 0 won't be possible to boot in this way).
 +  * After 15-20 seconds from the boot, release the button.
 +  * Now connect the port "​eth2"​ on the mikrotik to a proper device. It should show the openwrt interface, reachable on 192.168.1.1 .
 +
 +From the openwrt interface loaded, via telnet, we can do the following:
 +<​file>​
 +wget2nand http://​downloads.openwrt.org/​attitude_adjustment/​12.09/​ar71xx/​nand/​
 +# wait until "Image written, you can now reboot. Remember to change the boot source to Boot"
 +# but we don't have to change nothing because we won't press the reset button that enables the tftp from bootloader.
 +</​file>​
 +
 +===== Basic configuration =====
 +-> [[doc:​howto:​basic.config|Basic configuration]] After flashing, proceed with this.\\
 +Set up your Internet connection, configure wireless, configure USB port, etc.
 +
 +===== Specific Configuration =====
 +==== Interfaces ====
 +
 +The default network configuration is:
 +^ Interface Name ^ Description ^ Default configuration ^
 +| br-lan (eth0, eth1.1) | LAN | 192.168.1.1/​24 | 
 +| eth1.2 | WAN | DHCP | 
 +
 +
 +==== Switch Ports (for VLANs) ====
 +
 +The default switch configuration is:
 +^ Board      ^ Switch ​  ^ Port   ^ VLAN   ^ Interface ​  ^
 +|            |    0     | CPU    |   ​1 ​   |             |
 +| Eth5       ​| ​   0     ​| ​  ​1 ​   |   ​1 ​   |    eth0     |
 +| Eth2       ​| ​   0     ​| ​  ​2 ​   |   ​1 ​   |    eth0     |
 +| Eth3       ​| ​   0     ​| ​  ​3 ​   |   ​1 ​   |    eth0     |
 +| Eth4       ​| ​   0     ​| ​  ​4 ​   |   ​1 ​   |    eth0     |
 +|            |    0     ​| ​  ​5 ​   | off    |             |
 +|            |    1     | CPU    | 1/2    |             |
 +| Eth9       ​| ​   1     ​| ​  ​1 ​   |   ​1 ​   |      eth1.1 |
 +| Eth6       ​| ​   1     ​| ​  ​2 ​   |   ​1 ​   |      eth1.1 |
 +| Eth8       ​| ​   1     ​| ​  ​3 ​   |   ​1 ​   |      eth1.1 |
 +| Eth7       ​| ​   1     ​| ​  ​4 ​   |   ​1 ​   |      eth1.1 |
 +| Eth1/​PoE ​  ​| ​   1     ​| ​  ​5 ​   |   ​2 ​   |      eth1.2 |
 +
 +=== ''/​etc/​config/​network''​ every port usable as single port ===
 +<​file>​
 +config interface '​loopback'​
 +      ​option ifname '​lo'​
 +      ​option proto '​static'​
 +      ​option ipaddr '​127.0.0.1'​
 +      ​option netmask '​255.0.0.0'​
 +
 +config switch
 +      ​option name '​switch0'​
 +      ​option reset '​1'​
 +      ​option enable_vlan '​1'​
 +
 +# eth5
 +config switch_vlan
 +      ​option device '​switch0'​
 +      ​option vlan '​1'​
 +      ​option ports '0t 1'
 +
 +# eth2
 +config switch_vlan
 +        option device '​switch0'​
 +        option vlan '​2'​
 +        option ports '0t 2'
 +
 +# eth3
 +config switch_vlan
 +        option device '​switch0'​
 +        option vlan '​3'​
 +        option ports '0t 3'
 +
 +# eth4
 +config switch_vlan
 +        option device '​switch0'​
 +        option vlan '​4'​
 +        option ports '0t 4'
 +
 +config switch
 +       option name '​switch1'​
 +       option reset '​1'​
 +       option enable_vlan '​1'​
 +
 +# eth9
 +config switch_vlan
 +       option device '​switch1'​
 +       option vlan '​1'​
 +       option ports '0t 1'
 +
 +# eth6
 +config switch_vlan
 +        option device '​switch1'​
 +        option vlan '​2'​
 +        option ports '0t 2'
 +
 +# eth8
 +config switch_vlan
 +        option device '​switch1'​
 +        option vlan '​3'​
 +        option ports '0t 3'
 +
 +# eth7
 +config switch_vlan
 +        option device '​switch1'​
 +        option vlan '​4'​
 +        option ports '0t 4'
 +
 +# eth1
 +config switch_vlan
 +        option device '​switch1'​
 +        option vlan '​5'​
 +        option ports '0t 5'
 +</​file>​
 +
 +==== Failsafe mode ====
 +-> [[doc:​howto:​generic.failsafe]]
 +
 +==== Buttons ====
 +-> [[doc:​howto:​hardware.button]] on howto use and configure the hardware button(s).
 +
 +The Routerboard 493G has one software reset button.
 +^ BUTTON ​  ^ Event   ^
 +| Reset    | reset   |
 +
 +
 +==== Micro-SD-Card-Reader ====
 +
 +The SD-card reader is now supposed to work, but the needed patch is currently not in trunk. You will find the ticket with history here: https://​dev.openwrt.org/​ticket/​12349
 +
 +Hence precompiled images with working SD-card reader is not yet available from the OpenWrt server. Until that is resolved, you can find compiled kernel and rootfs here:
 +http://​ubuntuone.com/​1bZTk4vlKwroZezcdeJa4l
 +http://​ubuntuone.com/​2V1BoearwvvMOsNzUz7mcx
 +
 +Provide them on a web-server, or copy them manually over to the kernel and rootfs partitions on the nand.
 +
 +==== USB ====
 +
 +The USB-port of the RB493G is a **shameful chapter of Mikrotik engineering**.
 +
 +The USB-standard demands a 5VDC-power-supply on the USB-socket, but Mikrotik tried to save a few cents for a voltage converter. So one has to buy a power-injector from Mikrotik and any 5VDC-power-supply. Pray the plug of your power-supply fits into the power-injector! Just using a powered USB-hub doesn'​t solve the problem, as USB-hubs only enumerate/​register with the host-controller when 5VDC is supplied by the host-controller.
 +
 +Reliable vendors just update their PCB-layout, but Mikrotik sells that **non-standard/​sub-standard** PCB-layout **for years**, now.
 +
 +The Routerboard has a OHCI-controller for USB 1.x and a EHCI-controller for USB 2.0.
 +
 +See [[doc:​howto:​usb.essentials]] for configuration.
 +
 +===== Hardware =====
 +==== Info ====
 +| **[[wp>​Instruction set|Architecture]]:​** ​ | [[wp>​MIPS architecture|MIPS]]-BE ​                   |
 +| **Vendor:​** ​                              | [[wp>​Mikrotik]] / [[wp>​Qualcomm Atheros]] ​          |
 +| **[[doc:​techref:​Bootloader]]:​** ​          | MikroTik RouterBoot (Rescue- and Main-Bootloader) ​  |
 +| **Default Operating System:​** ​            | MikroTik RouterOS v4, Level5-license ​               |
 +| **[[doc:​hardware:​soc|System-On-Chip]]:​** ​ | Atheros AR7161 rev 2 |
 +| **[[doc:​hardware:​cpu|CPU]]/​Speed** ​       | MIPS 24Kc rev 00019374 680/800 Mhz |
 +| **Flash-Chip:​** ​ | Samsung NAND 128MiB 3,3V 8-bit or\\ ST Micro NAND 01GW3B2CN6 or\\ Toshiba NAND 128MiB 3,3V 8-bit |
 +| **Flash size:​** ​ | 128 MiB NAND-Flash ​                |
 +| **Micro-SD:​** ​   | 1x Micro-SD-socket (probably SPI)  |
 +| **RAM:​** ​        | 256 MiB DDR-SDRAM ​                 |
 +| **Wireless:​** ​   | optional via 3x Mini-PCI IIIA/​B ​   |
 +| **Ethernet:​** ​   | 9x 10/​100/​1000Base-T(X) (2x Atheros AR8316-5-port-switch with VLAN support [[doc:​techref:​swconfig]] |
 +| **Internet:​** ​   | n/​a/​xDSL/​DOCSIS/​3g/​LTE ​  |
 +| **USB:​** ​        | 1x 2.0 (unpowered) ​      |
 +| **[[doc:​hardware:​port.serial|Serial]]:​** ​  | [[#​Serial|YES 1x Sub-DB9 RS-232C asynchronous]] ​  |
 +| **[[doc:​hardware:​port.jtag|JTAG]]:​** ​      | [[#​JTAG|Maybe]] (contatcs on PCB, not tested) ​    |
 +| **LED:​** ​            | Power, NAND activity, 5x user LED              |
 +| **Power options:​** ​  | 10..28 VDC Power-over-Ethernet or Power-Jack ​  |
 +| **Power consumption:​ ** | ~3 Watt, up to 10 Watt for MiniPCI-cards,​ maximum 16 Watt |
 +| **Dimensions:​** | 160 mm x 105 mm, 189 grams |
 +
 +==== Photos ====
 +
 +Casing: Mikrotik case CA493 with two N-pigtails and -antennas (antennas are ALFA ARS-N19CW, 2.4GHz 9dBi - pigtails and antennas not included in enclosure package)\\
 +{{media:​mikrotik:​ca493_case_antennas.jpg?​400}}
 +
 +//​Front://​\\
 +Casing: Mikrotik CA493 with serial port, Ethernet-port,​ LEDs and power-connector of Routerboard RB493G\\
 +{{media:​mikrotik:​ca493_frontside.jpg?​400}}
 +
 +//Back://\\
 +Casing: Mikrotik CA493 with two N-pigtails (not included), multi-purpose hole (e.g. N-connector,​ Swivel-antenna,​ ...) and ground-screw\\
 +{{media:​mikrotik:​ca493_backside.jpg?​400}}
 +
 +//​Left/​Top://​
 +Casing: Mikrotik CA493 with eight Ethernet-ports of Routerboard RB493G\\
 +{{media:​mikrotik:​ca493_left_top.jpg?​400}}
 +
 +
 +//Right://
 +Casing: Mikrotik CA493 with venting holes\\
 +{{media:​mikrotik:​ca493_right.jpg?​400}}
 +
 +
 +//Bottom://
 +Casing: Mikrotik CA493\\
 +{{media:​mikrotik:​ca493_bottom.jpg?​400}}
 +
 +Casing opened:\\
 +Casing: Mikrotik CA493 with two N-pigtails (not included), Routerboard 493G and Routerboard R52nM (Wifi-card)\\
 +{{media:​mikrotik:​ca493_case_pcb.jpg?​400}}
 +
 +==== Opening the case ====
 +
 +  *To remove the cover just unscrew the 4 screws (2 left side, two right side)
 +
 +//Main PCB top//\\
 +{{media:​mikrotik:​rb493_pcb-top.jpg?​600}}
 +
 +  * Power socket
 +  * 2x LED
 +  * 1x 1000Base-T with proprietary POE
 +  * 1x Sub-D9 Serial Port (Console by default)
 +  * 8x 1000Base-T Port
 +  * 1x Reset-contacts
 +  * 2x Atheros AR8316 (under heatsinks)
 +  * 1x JTAG-contacts
 +  * 1x USB 2.0 (unpowered)
 +  * 3x MiniPCI Type IIIA/B
 +  * 2x RAM SAMSUNG K4H510838G-LCCC
 +  * 2x regulated Fan-connector 3.3V 500mA
 +  * 2x regulated Fan connector main voltage 500mA
 +  * 4x Screw holes
 +
 +//Main PCB bottom//\\
 +{{media:​mikrotik:​rb493_pcb-bottom.jpg?​600}}
 +
 +  * Flash: ST NAND01GW382CNb
 +  * CPLD:  XILINX XC9536XL
 +  * Flash: microSD-Socket
 +  * RAM:   2x SAMSUNG K4H510838G-LCCC
 +
 +==== Serial ====
 +The Routerboard has one serial interface in form of a Sub-D9-socket. By default it provides a serial console.
 +It can be accessed with a Null-Modem-Cable (115200, 8N1, no handshaking!).
 +
 +==== JTAG ====
 +There are seven contacts named "​JTAG"​ between USB- and MiniPCI-Socket,​ but not tested.
 +
 +===== Debricking =====
 +-> [[doc:​howto:​generic.debrick]]
 +
 +In worst case keep "​Reset"​-button pressed when powering on the Routerboard to access the recovery-boot-loader via serial console.
 +That way the Routerboard can be re-flashed with a RouterOS-image (NPK-file) using the origin MikroTik-Netinstall-software (BOOTP/​TFTP).
 +
 +===== Hardware Mods =====
 +As a beginner, you really should inform yourself about [[doc:​hardware:​soldering]] in general and then even obtain some experience!
 +
 +==== USB-Modification ====
 +
 +Components:
 +
 +| 1x | PCB |
 +| 1x | USB-2.0-dual-A-socket,​ e.g., [[http://​dx.com/​p/​diy-dual-usb-female-type-a-180-degree-dip-socket-connector-silver-10-piece-pack-127653|these]]. |
 +| 1x | USB-2.0- A-plug, e.g., [[http://​dx.com/​p/​diy-usb-4-pin-female-type-a-smt-socket-connector-silver-10-piece-pack-127642|these]]. |
 +| 1x | Traco TSR 1-2450 step-down-converter 5VDC/1A (doesn'​t need any other components like capacitors or heatsink). As of this writing you will find the LM7805V voltage regulator at [[http://​dx.com/​p/​lm7805l-5v-voltage-regulator-ics-10-pcs-157382 | DealExtreme]] |
 +| 1x | Multifuse 60VDC/0,5A I<​sub>​hold</​sub>/​1A I<​sub>​trip</​sub>​ |
 +
 +Proto-type and diagrams/​layouts aren't beauties, but maybe someone with more Cadsoft-Eagle-experience can make a nice circuit-diagram and a real PCB-layout: {{media:​mikrotik:​rb493g_usb-mod.zip|Eagle files and datasheets}} ;-)
 +
 +Rudimentary circuit-diagram with USB-2.0 data-port (1) and generic USB-2.0 charger port (2), both supplied by a step-down-converter via the fan-connector of the RB493G:\\
 +{{media:​mikrotik:​rb493g_usb-mod_circuit-diagram.png?​400}}
 +
 +Rudimentary PCB-layout, not applicable:​\\ ​
 +{{media:​mikrotik:​rb493g_usb-mod_pcb.png?​400}}
 +
 +USB-mod prototype top-view:​\\ ​
 +{{media:​mikrotik:​rb493g_usb-mod-top.jpg?​400}}
 +
 +USB-mod prototype bottom-view:​\\ ​
 +{{media:​mikrotik:​rb493g_usb-mod-bottom.jpg?​400}}
 +
 +USB-mod prototype attached:​\\ ​
 +{{media:​mikrotik:​rb493g_usb-mod-attached.jpg?​400}}
 +
 +===== Tags =====
 +[[meta:​tags|How to add tags]]
 +
 +{{tag>​AR7161 GigabitEthernet 2NIC 0WNIC 9Port USB DetachableAntenna 256RAM 128Flash gt32flash miniPCI 3miniPCI MIPS MIPS32 24Kc}}