Talk:Multitone Paging
In my QTH there is also a similar pager signal. I have inspected it and the samples on this page. This protocol is definitely not Multitone MK7.
MK7 protocol is very similar to pocsag. It's described in this document: https://www.manualslib.com/manual/1071975/Multitone-Rpr-551is.html
Paging signals on this page contain very short preamble like 20 bits or so. Pocsag and MK7 preamble (continous 01010101) is at least 576 bits. Also if the data is manchester decoded to bits, it doesn't contain any of those sync words (btw. same one that pocsag uses) or other bit sequences described in MK7 protocol.
This signal on this page of could be MK6 of course but it's hard to believe it would be so different. Why would a company develop their own protocol and then make a new protocol which is actually just a pocsag copy?
So I guess this is some other pager manufacturers protocol. But what is that manufacturer?
-Pedro
Astute observation. I'm not sure where this was confirmed, but it was confirmed enough that I believed it was multitone. I didn't have any evidence suggesting otherwise, except now that you did a protocol check it may not be multitone after all.
There could be other factors as to why the bits dont match, but for now its worth exploring.
--Cartoonman (talk) 23:27, 18 May 2020 (NZST)
Cartoonman is exactly right mostly. Ive analyzed the signals of POCSAG and this, and unfortunately these bits are in NO way matched up or similarly coded.
Multitone is a *propietary* standard developed by them, they do not use the same bytes, but the same *modulation* being FSKFrequency-Shift Keying. Theres the key difference. Also, some of multitones signals are basebanded with an FMFrequency Modulation carrier sometimes to appear like it has an FMFrequency Modulation spectrum instead of the FSKFrequency-Shift Keying variant...
A simple example of POCSAG's in HEX format would be a message dump without an address (maybe 0000000) would be this as a TONE ONLY message: ||0x7CD215D87A89C1977A89C1977A89C1977A89C1977A89C1977A89C1977A89C1977A89C1977A89C1977A89C1977A89C1977A89C1977A89C1977A89C1977A89C1977A89C197.|| It is supposed to be a 17 byte vector and repeats twice.
Multitone does not follow this. They dont use a straight up alternating sequence and instead use a sync header of whatever bytes then the message.. << that doesnt sound at ALL similar to multitone's propietary protocol...The description should be changed and/or this moved to th UNID section for further analysis... --> Yalek W
