diff --git a/content/experiment-control/sinara-core.md b/content/experiment-control/sinara-core.md
index d28f5d2..1e1a061 100644
--- a/content/experiment-control/sinara-core.md
+++ b/content/experiment-control/sinara-core.md
@@ -36,7 +36,7 @@ One of the main devices in the Sinara family is the 1123 Processor (codenamed Ka
 
 ##### Sinara 2118/2128/2138 TTL cards
 
-For simple TTL signals, we offer I/O cards in the EEM form factor with 8 channels over BNC (2118), SMA (2128) or MCX (2138) connectors. The IOs are divided into two banks of 4, with per-bank ground isolation. The direction (input/output) and termination (high-Z/50R) is selectable on a per-channel basis via I2C or on-board switches. Outputs can supply 5V into 25Ω, and can tolerate an indefinite short-circuit to ground.
+For simple TTL signals, we offer I/O cards in the EEM form factor with 8 channels over BNC (2118), SMA (2128) or MCX (2138) connectors. The IOs are divided into two banks of 4, with per-bank ground isolation. The direction (input/output) and termination (high-Z/50R) is selectable on a per-channel basis via I2C or on-board switches. The open circuit voltage of outputs is 5V, and outputs can supply a valid TTL level into 50Ω and tolerate an indefinite short circuit to ground.
 
 More information: <a href="https://github.com/sinara-hw/DIO_BNC/wiki" target="_blank" rel="noopener noreferrer">BNC card</a> <a href="https://github.com/sinara-hw/DIO_SMA/wiki" target="_blank" rel="noopener noreferrer">SMA card</a>