# Maximum cable lenght between two Piicodev moduls **URL:** \ **Category:** Product Questions\ **Created:** [23 August 2021 13:51 UTC](https://forum.core-electronics.com.au/t/maximum-cable-lenght-between-two-piicodev-moduls/11134 "2021-08-23T13:51:46Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![Farhad164597](https://avatars.discourse-cdn.com/v4/letter/f/a4c791/32.png) [@Farhad164597](https://forum.core-electronics.com.au/u/Farhad164597)\ **Post date:** [23 August 2021 13:51 UTC](https://forum.core-electronics.com.au/t/maximum-cable-lenght-between-two-piicodev-moduls/11134/1 "2021-08-23T13:51:47Z")
Hi team, How long would be the maximum length of a cable for connecting PiicoDev modules together? e.g. 4 Wire Telephone Cable, or CAT5e cable. Thanks, ---
**Author:** ![Trent5487676](https://yyz2.discourse-cdn.com/flex028/user_avatar/forum.core-electronics.com.au/trent5487676/32/4583_2.png) [@Trent5487676](https://forum.core-electronics.com.au/u/Trent5487676)\ **Post date:** [24 August 2021 05:46 UTC](https://forum.core-electronics.com.au/t/maximum-cable-lenght-between-two-piicodev-moduls/11134/2 "2021-08-24T05:46:35Z")
Hi Farhad, The PiicoDev modules use the I2C protocol to communicate so their limitations are based on that. As the name, Inter-integrated-circuit implies it’s made for very short distances. Some sources say [around 1 meter](http://www.mosaic-industries.com/embedded-systems/sbc-single-board-computers/freescale-hcs12-9s12-c-language/instrument-control/i2c-bus-specifications#:~:text=So%20the%20maximum%20bus%20length,within%20an%20otherwise%20shielded%20enclosure.) is the longest you can get. Ultimately it is a result of the capacitance between your cables and the pull up resistance of your data lines. There is some discussion on stack exchange here: [Maximum I2C Bus Length? - Electrical Engineering Stack Exchange](https://electronics.stackexchange.com/questions/106265/maximum-i2c-bus-length) And a look into the mathematics behind the limitations here: [I2C Cabling | Analog Devices](https://www.analog.com/en/technical-articles/i2c-cabling.html) ---
**Author:** ![Farhad164597](https://avatars.discourse-cdn.com/v4/letter/f/a4c791/32.png) [@Farhad164597](https://forum.core-electronics.com.au/u/Farhad164597)\ **Post date:** [24 August 2021 09:15 UTC](https://forum.core-electronics.com.au/t/maximum-cable-lenght-between-two-piicodev-moduls/11134/3 "2021-08-24T09:15:43Z")
Thank you! Can I use Adafruit LTC4311 I2C Extender at the end ( or beginning) of a chain of Piicodev modules. ---
**Author:** ![Liam](https://yyz2.discourse-cdn.com/flex028/user_avatar/forum.core-electronics.com.au/liam/32/3562_2.png) [@Liam](https://forum.core-electronics.com.au/u/Liam)\ **Post date:** [25 August 2021 01:21 UTC](https://forum.core-electronics.com.au/t/maximum-cable-lenght-between-two-piicodev-moduls/11134/4 "2021-08-25T01:21:16Z")
Hi Farhad, Yeah, it looks like this one would be best placed at the start of the chain. JP from Adafruit has a great video on it here: [JP’s Product Pick of the Week 12/1/20 LTC4311 I2C Terminator @adafruit @johnedgarpark - YouTube](https://youtu.be/MaTdmCq4UH0) If you are keen on doing some conversion you can use a [voltage to current converter](https://core-electronics.com.au/gravity-analog-current-to-voltage-converter-for-4-20ma-application.html) to send the signal down a massive cable. Liam.