diff --git a/content/retro/modem.md b/content/retro/modem.md
index db16b9b..08e7991 100644
--- a/content/retro/modem.md
+++ b/content/retro/modem.md
@@ -7,12 +7,12 @@ Connect in to dn42 using a real physical modem.
 
 {{<hint danger>}}
 **Health warning**: dialing in to dn42 can be rewarding and great fun, but using modems
-over VOIP is flakey at the best of times and getting it to work can be a
+over VoIP is flakey at the best of times and getting it to work can be a
 frustrating experience. This is very much an experimental service.
 {{</hint>}}
 
 The burble.dn42 dialup service allows you to dial in to dn42 via a modem. The
-modem is reachable via VOIP and connected to a PPP server, allowing you to log in
+modem is reachable via VoIP and connected to a PPP server, allowing you to log in
 and obtain full dn42 IPv4 connectivity. 
 
 #### Endpoints
@@ -59,3 +59,6 @@ The video shows an example connecting using minicom and pppd on linux.
 
 <video src="/retro/modem.webm" width="720" height="449" autoplay="true" loop="true"></video>
 
+## Using a software modem
+
+[JerryXiao](https://jerryxiao.cc/dn42) has created instructions for connecting using D-Modem, a software modem that can connect directly over VoIP. The instructions and D-Modem software are available in the [dn42 gitea repository](https://git.dn42.dev/JerryXiao/D-Modem/src/branch/master/README.jerry.md).
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