# Probe wiring for ITC308 and IHC200 units **URL:** \ **Category:** Questions & Answers\ **Created:** [January 25, 2025, 7:17pm UTC](https://community.inkbird.com/t/probe-wiring-for-itc308-and-ihc200-units/166412 "2025-01-25T19:17:49Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![Olivemuk](https://avatars.discourse-cdn.com/v4/letter/o/8dc957/32.png) [@Olivemuk](https://community.inkbird.com/u/Olivemuk)\ **Post date:** [January 25, 2025, 7:17pm UTC](https://community.inkbird.com/t/probe-wiring-for-itc308-and-ihc200-units/166412/1 "2025-01-25T19:17:49Z")
Hi all I have a tiny hole through which it run my probes and the only way I’ll do it is by cutting the probe wire, running it through, and rejoining. I want to attach a 2.5mm connector as my units don’t have removable probes. However does anyone know how many wires are in the 308 temp prob and the 200 humidity probes? I need to know this so I can get the correct 2.5mm connectors. Olly ---
**Author:** ![jediscuba](https://avatars.discourse-cdn.com/v4/letter/j/45deac/32.png) [@jediscuba](https://community.inkbird.com/u/jediscuba)\ **Post date:** [January 31, 2025, 3:44pm UTC](https://community.inkbird.com/t/probe-wiring-for-itc308-and-ihc200-units/166412/2 "2025-01-31T15:44:06Z")
The cable connecting the sensor and unit has only 2 wires. The sensor is an NTC Resistor. I’ve even substituted other 10K ohm NTC units and even extended the wire by 10 feet. There is a negligible offset in the reading and you can calibrate to correct this. ---
**Author:** ![Olivemuk](https://avatars.discourse-cdn.com/v4/letter/o/8dc957/32.png) [@Olivemuk](https://community.inkbird.com/u/Olivemuk)\ **Post date:** [January 31, 2025, 5:46pm UTC](https://community.inkbird.com/t/probe-wiring-for-itc308-and-ihc200-units/166412/3 "2025-01-31T17:46:39Z")
Thanks. Any idea of the IHC humidity wiring? And did you use a generic temp sensor online?