[Today’s run: nothing yet]<\/p>\n
I have this NiCOM NT250 FM broadcast transmitter which we are going to use for our LPFM station\u00a0 (WMFH-LP).\u00a0 The thing has\u00a0 9-pin serial port on the back and NiCOM kindly sent me the software which talks to the transmitter.\u00a0 The software is a simple windows executable. It will let me change the frequency, turn the output power off\/on, and it shows me the forward and reflected power output.<\/p>\n
That’s all good stuff, particularly the ability to turn the RF off.<\/p>\n
I asked NiCOM for a spec about the serial commands and never heard back from them.<\/p>\n
So, today I finally had some success reverse-engineering the connection.\u00a0 I downloaded a program called Free Serial Analyzer.\u00a0 It can show me the serial port activity between the NiCOM control program and the transmitter.\u00a0 Using that I figured out this much:<\/p>\n
Serial settings:\u00a0\u00a0 4800 8 N 1\u00a0 (no flow control)<\/p>\n
sent:\u00a0 ctl-D\u00a0 (0x04)\u00a0\u00a0 received: 140 \u00a0 (in ASCII followed by a ‘.’) \/\/ forward power<\/p>\n
sent: ctl-E\u00a0 (0x05)\u00a0\u00a0 received: 3\u00a0 (in ASCII followed by a ‘.’) \/\/ reflected power<\/p>\n
sent: ctl-F\u00a0 (0x06)\u00a0\u00a0 received: 4.0\u00a0 (etc) \/\/ firmware version #<\/p>\n
sent: ctl-G (0x07)\u00a0 received 159\u00a0 \/\/ unknown<\/p>\n
sent: ctl-H (0x08)\u00a0 received 9\u00a0\u00a0 \/\/ ???<\/p>\n
sent ctl-I (0x09)\u00a0 received 0995\u00a0 \/\/\u00a0 frequency setting<\/p>\n
sent ctl-J (0x0A)\u00a0 received 9 \/\/ ???<\/p>\n
sent ctl-K (0x0B) received 9 \/\/\u00a0 RF power turn on<\/p>\n
sent ctl-C (0x0C) received 0 \/\/ RF power turn off<\/p>\n
The windows program has some method of changing the frequency.\u00a0 And it also shows the current temperature.\u00a0 Obviously I am missing some of the command set. I now know how to read forward and reflected power, and how to turn the power on and off.\u00a0 That’s really all I need.<\/p>\n","protected":false},"excerpt":{"rendered":"
[Today’s run: nothing yet] I have this NiCOM NT250 FM broadcast transmitter which we are going to use for our LPFM station\u00a0 (WMFH-LP).\u00a0 The thing has\u00a0 9-pin serial port on the back and NiCOM kindly sent me the software which talks to the transmitter.\u00a0 The software is a simple windows executable. It will let me […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[13],"tags":[],"class_list":["post-4914","post","type-post","status-publish","format-standard","hentry","category-classic-book-radio"],"_links":{"self":[{"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=\/wp\/v2\/posts\/4914","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=4914"}],"version-history":[{"count":4,"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=\/wp\/v2\/posts\/4914\/revisions"}],"predecessor-version":[{"id":4918,"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=\/wp\/v2\/posts\/4914\/revisions\/4918"}],"wp:attachment":[{"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=4914"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=4914"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/w0ep.us\/OM\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=4914"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}