Cisco SG220 / SF220 Series

Model SoC PoE Comment
SG220-26 RTL8382M
SG220-26P RTL8382M
SG220-50 RTL8393M
SG220-50P RTL8393M
SF220-24 RTL8332M 10/100 ports only
SF220-24P RTL8332M 10/100 ports only
SF220-48 RTL8353M 10/100 ports only
SF220-48P RTL8353M 10/100 ports only

All models share the same firmware image. The image format is the same as the bix format, used by the Zyxel GS1900 series switches.

The SG220-26 and SG220-26P appear to use the same board, although some components related to the PoE management are missing on the SG220-26's main board

  • 2× RTL8218B PHYs
  • RTL8231 GPIO expander
    • 1× MIIM mode (virtual MIIM, address 31)
    • 2× Shift register mode (LED_CLK, LED_DAT)
  • Winbond W631GU8MB (128MiB DDR3 SDRAM)
  • Macronix MX25L25635F, Winbond 25Q256FVFG (32MiB SPI flash)
  • Sipex SP3232, ADM3202 RS-232 transceiver


  • Internal GPIO:
    • gpio1: active low, SoC reset
    • gpio2: MDC line to RTL8231
    • gpio3: MDIO line to RTL8231
  • RTL8231 @ phy address 31:
    • gpio0-4: device ID
    • gpio5-6: device hardware revision
    • gpio27: reset button
    • gpio16: watchdog state (active low)
    • gpio34: (unknown, maybe watchdog related, initialised to 1)
    • gpio9: watchdog feed (10s)
    • gpio24: SFP25 "OE" (MOD_DEF0?, used to detect module)
    • gpio11: SFP25 loss of signal (used to detect media change)/
    • gpio17: SFP25 transmit disable
    • gpio28: SFP26 "OE" (MOD_DEF0?)
    • gpio12: SFP26 loss of signal
    • gpio18: SFP26 transmit disable
    • gpio15: SCK for SFP25, SFP26, TERM1, TERM2, FAN1, FAN2 (shared I2C clock)
    • SDA lines:
      • gpio13: SFP25
      • gpio14: SFP26
      • gpio29: TERM1, TERM2 (26P only)
      • gpio31: FAN1 (26P only)
      • gpio33: FAN2 (26P only)


All LEDs are controlled by the port LED peripheral:

  • Ports 1-24: Green Link/Act LED (idx 0), amber PoE LED (idx 1) (26P only)
  • Ports 25-26: Green Link/Act LED (idx 0), green gigabit LED (idx 1)
  • Green status LED: user controlled LED for port 27, index 1
  • Amber status LED: user controlled LED for port 28, index 1

The green and amber device status LEDs are wired in anti-parallel, and only one can be enabled at a time.


Present only on the SG220-26P.

  • FAN1: TC655 at 0x1B. Does not appear to be present on SG220-26P.
  • FAN2: TC655 at 0x1B. The TC655 controls both fans behind the PSU of the SG220-26P.
  • TEMP1: LM75A at 0x49
  • TEMP2: LM75A at 0x4B


The JTAG header uses the MIPS eJTAG pin-out, with pin 12 (key) bound to ground.

  • J4.1 TRST#: 1k pull-down
  • J4.3 TDI: 10k pull-up
  • J4.7 TMS: 10k pull-up
  • J4.9 TCK: 10k pull-up
  • J4.11 SRST#: 10k pull-up
TRST# |  1   2 | GND
  TDI |  3   4 | GND
  TDO |  5   6 | GND
  TMS |  7   8 | GND
  TCK |  9  10 | GND
SRST# | 11  12 | GND
  N/C | 13  14 | VCC

Board pictures

Board Pictures
SG220-26P overview SG220-26P overview
SG220-26 main board SG220-26 main top
SG220-26P main board SG220-26P main top SG220-26P main board backside SG220-26P detail: flash, RAM, DC/DC SG220-26P I/O, SFP phy
SG220-26P PoE daughter board SG220-26P PoE board SG220-26P PoE board backside SG220-26P PoE management chip
SG220-26P I/O daughter board SG220-26P I/O daughter board SG220-26P I/O daughter board backside
SG220-26P serial daughter board SG220-26P serial port daughter board SG220-26P serial port daughter board backside
  • cisco-sx220.txt
  • Last modified: 2022/08/24 23:21
  • by raylynnknight