README.devices: Document enabling GW Instek GDM-397 serial output mode.

diff --git a/README.devices b/README.devices
index 2b66cd0104b4661ba66f705bbeae2ca3e905f3a6..37e0525c44330bd307999ebc47c8e85c79a4a24b 100644 (file)
--- a/README.devices
+++ b/README.devices
@@ -390,6 +390,7 @@ a short list for convenience:
       'SI232 online' (28-29S) or 'SI232 store' (22-26x). The interface must
       be configured to the same baud rate as the host (default 9600).
       Multimeter and interface must be configured to the same address.
+ - GW Instek GDM-397: Press the "REL/RS232C (USB)" button for roughly 1 second.
  - MASTECH MS6514: Press the "Setup/PC-Link" button for roughly 3 seconds.
  - Metrix MX56C: Press the PRINT button to have the meter send acquisition
    data via IR. Hold the PRINT button to adjust the meter's transmission