EPS Connector Pinout (Source Side) for Brocade ICX6450
The following table outlines the 20-pin EPS connector layout on the power supply side (EPS1500 / EPS4000) used for powering Brocade ICX6450 switches. The cable between the power supply and switch is wired 1:1, meaning each pin has the same function on both ends. Each pin is described by its signal type, voltage level or logic state, and functional role. Data is based on official Brocade documentation and technical manuals.
Pin Signal Type Voltage / Logic Level Function Control Notes
1 Control Signal TTL logic 12V_EPS – Indicates presence of +12 V rail Likely open-collector (pull-up at switch side)
2 Control Signal TTL logic 12V_EPS – Same as pin 1 Open-collector
3 Control Signal TTL logic EPS_PG – “Power Good” signal for 12 V/54 V rails Open-collector
4 Power Output +12 V 12V+ – +12 V rail for switch power –
5 – – Not connected –
6 – – Not connected –
7 Control Signal TTL logic 54V_EPS – Indicates presence of +54 V rail (PoE) Open-collector
8 Control Signal TTL logic 54V_EPS – Same as pin 7 Open-collector
9 Power Output +54 V 54V+ – +54 V PoE power rail –
10 Control Signal TTL logic 54V-IS – Indicates load sharing is active Open-collector
11 Ground 0 V GND – Common ground for 12 V/54 V rails –
12 Ground 0 V GND – Same as pin 11 –
13 Control Signal TTL logic EPS_on – Enables power output when asserted Open-collector (input to PSU, similar to ATX PS_ON)
14 Return (Power) 0 V (–12 V reference) 12V- – Return line for +12 V –
15 Control Signal TTL logic EPS_PST – Indicates connector readiness Open-collector
16 – – Not connected –
17 Ground 0 V 54V_RTN – Return for +54 V rail –
18 Ground 0 V 54V_RTN – Same as pin 17 –
19 Return (Power) 0 V (–54 V reference) 54V- – Return line for +54 V –
20 – – Not connected –
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Control Signal Details
All control signals (pins 1, 2, 3, 7, 8, 10, 13, 15) operate as TTL-level logic signals. Based on Brocade documentation:
• 12V_EPS (pins 1–2) signals +12 V rail is active.
• EPS_PG (pin 3) is a Power Good output, confirming voltage stability.
• 54V_EPS (pins 7–8) indicates the presence of the +54 V PoE rail.
• 54V-IS (pin 10) provides load-sharing status.
• EPS_on (pin 13) functions similarly to ATX PS_ON — the switch asserts this signal to turn the PSU outputs on.
• EPS_PST (pin 15) likely indicates connector presence or readiness (handshake-type signal).
All of the above are likely open-collector signals, meaning the source either pulls the line to GND or leaves it floating, while the receiver side (typically the switch) includes pull-up resistors to 3.3 V or 5 V. A signal is asserted (active) when pulled low (GND). This open-drain signaling approach allows multiple sources to share the line safely.
Power outputs are direct: +12 V and +54 V are provided on pins 4 and 9, with respective returns on pins 14 and 19. Ground pins (11, 12, 17, 18) provide a common reference for all power rails and control lines. Pins 5, 6, 16, and 20 are unused (NC).
At least as 12V power supply with PicoPSU. 12 ATX power supplies with decent efficiency is not cheap.
