# External Trigger (digitalio) Problems **URL:** \ **Category:** Uncategorized\ **Created:** [May 23, 2013, 11:01am UTC](https://psychtoolbox.discourse.group/t/external-trigger-digitalio-problems/324 "2013-05-23T11:01:44Z")\ **Posts on this page:** 1\ **Page:** 1
**Author:** ![Allen\_Ingling](https://avatars.discourse-cdn.com/v4/letter/a/a183cd/32.png) [@Allen\_Ingling](https://psychtoolbox.discourse.group/u/Allen_Ingling)\ **Post date:** [May 23, 2013, 11:01am UTC](https://psychtoolbox.discourse.group/t/external-trigger-digitalio-problems/324/1 "2013-05-23T11:01:44Z")
I need to send an external trigger from my computer to a TMS Magstim device. I have previously been advised that this is the code I need: dio = digitalio('parallel','LPT1'); addline(dio,0:7,0,'out'); line = 1; % Set value to 0 (low) putvalue(dio.line(line),0); % Set value to 1 (high) putvalue(dio.line(line),1); % Set value to 0 (low) putvalue(dio.line(line),0); However it doesn't seem to work! The code produces these lines: Display Summary of DigitalIO (DIO) Object Using 'PC Parallel Port Hardware'. Port Parameters: Port 0 is port configurable for reading and writing. Port 1 is port configurable for reading. Port 2 is port configurable for reading and writing. Engine status: Engine not required. DIO object contains line(s): Index: LineName: HwLine: Port: Direction: 1 'Pin2' 0 0 'Out' 2 'Pin3' 1 0 'Out' 3 'Pin4' 2 0 'Out' 4 'Pin5' 3 0 'Out' 5 'Pin6' 4 0 'Out' 6 'Pin7' 5 0 'Out' 7 'Pin8' 6 0 'Out' 8 'Pin9' 7 0 'Out' But nothing happens on the machine end, even though it's set up to run. If anyone has any advice I would be grateful!