Tuesday, May 23, 2017

How to power Escort 9500ix with USB

This is is not related to IT but I feel like sharing it.  :)

I have an Escort 9500ix radar detector which is powered by 12v RJ-11 connector.  The stock power cord looks like below:

When I go travel, I want everything(GPS, camera, cell phone, tablet, radar detector, etc.) to be powered by USB so:
1) I don't have to carry the bulky power adapters. (especially when going through airport security)
2) I can use multi-port USB car charger (see below) instead of occupying a precious 12v cigarette power socket for each device.

I have no problem power the Garmin GPS as it uses standard 5V USB port.  However the Escort 9500ix radar detector uses 12V RJ-11 port.

So what I need is a 5V-to-12V step-up.  I want it to be small and integrated as I don't want to carry different kinds of modules/adapters.  Luckily I found one from eBay which looks like a USB-to-DC cable but with the step-up module built-in.

All I need to do is to cut the 2.1mm DC plug off and crimp a RJ-11 connector on.  Escort uses the two middle pins of the RJ-11 connector for power.  See picture below for pin-out.

The 5v-to-12v step-up cable doesn't necessarily have a consistent color code.  Thus you'll have to use a multi-meter to tell which wire is positive and which one is negative.  Once identified, insert the wires into the correct slot of the RJ-11 connectors.

The final product looks like below.

What if the cable is not long enough?  Easy, get a USB extension cord.

If you don't have a RJ-11 crimper (see below), you may also just cut and strip a regular telephone cord.  Then twist it with the step-up cable.  All you need is a scissors.

Monday, February 20, 2017

IP Calculator Functions for Spreadsheet

Spreadsheet (e.g. Microsoft Excel) is a very powerful tool for network engineers.  I use spreadsheet to build network configuration scripts, especially for large scale deployment/migration.  For example, how about crating 100 VLANs and their corresponding SVIs with HSRP?

Due to the format of IP address we're accustomed to, it's not very easy to build configuration scripts with native spreadsheet functions.  For example:

Given a IP subnet "", what is the last host IP in the subnet?  Or what is the wildcard of the subnet?

I've tried different tools and add-ons and settled for "IP Calculator for Excel" (http://trk.free.fr/ipcalc/) due to the following reasons:

1) Integrated and Unified - it was built with VBA macros.  You may use the functions just the same way as the native Excel functions.  e.g. "=ipAdd(A1,2)" takes the IP address from cell A1 and returns an IP address with addition 2.  Thus you may build formulas the same way you do in any regular Excel spreadsheet.

2) Light weighted - the macro is less than 40k.  Thus it won't add too much weigh on your spreadsheet.

3) No EXE.  It is embedded into spreadsheet as macro.  Thus it doesn't trigger any security or policy alerts.  Of course, you still have to enable macros from Excel though.

4) IPv4 and IPv6 support.

If you're a network engineer who works on large scale network, take a look at this tool.  It'll save you tons of time and human errors.