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toh:mikrotik:rb493g [2013/01/14 17:08]
toh:mikrotik:rb493g [2016/02/02 20:30] (current)
danitool [Tags]
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 +====== 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}}