MR8100

MR8100 – UNIDEN Scanning Mobile Receiver 8100

Data Protocol Serial port parameters: Baud Rate Parity Data Bits Stop Bits 1200 NONE 8 1

Every character sent to the radio is echoed back to the PC. It is therefore important to always flush the input buffer and “confirm” the received characters match those sent. There are two types of commands that can be sent to the radio:

1. Program a Channel / Bank Label / Priority; (21 bytes):

       <CC> <type> <EE> <data> <text>

2. Request data from the radio; (3 bytes):

       <DD> <type> <EE>
   

   … radio responds with 18 bytes: <data> <text>

Where:

• <CC>, <DD>, and <EE> are single byte hex values: 204, 221, 238 decimal respectively.
• <type>; (1 byte): one of 3 choices: Priority or Bank Label or Channel…
  •  
  • <0x> – Priority; <data>; (4 bytes): <bc>, <?>, <bank 1–8>, <bank 9,10>
    This sets or shows the priority channel assignment and the current active banks. Also sets or shows 16 character “hidden” text for auxilliary usage.
    • <bc> see below
    • <?>: 0 (unknown)
    • <bank 1–8>; (1 byte): bits are as follows:
      • <0> – bank 5
      • <1> – bank 6
      • <2> – bank 7
      • <3> – bank 8
      • <4> – bank 1
      • <5> – bank 2
      • <6> – bank 3
      • <7> – bank 4
    • <bank 9,10>; (1 byte): bits are as follows:
      • <0> – ? (default to 0)
      • <1> – ? (default to 0)
      • <2> – ? (default to 0)
      • <3> – ? (default to 0)
      • <4> – bank 9
      • <5> – bank 10
      • <6> – ? (default to 0)
      • <7> – ? (default to 1)
  • <Bb> – Bank Label; <data>; (4 bytes): 0, 0, 0, 0
    This sets or shows the text associated with the bank. This is displayed briefly when a bank is switched to “active” during scanning by pressing a number key.
  • <bc> – Channel; <data>; (4 bytes): <flags>, <band>, <freq1>, <freq2>
    This sets or shows the channel frequency and additional attributes. Text may be numeric representation of frequency or any arbitrary channel label.
    <flags>; (1 byte):

    Bit(s)	Description
    <3:0>	0 (unknown)
    <4>	not L/O: 0, L/O: 1
    <5>	not USED: 0, USED: 1
    <6>	not SECURE: 0, SECURE: 1
    <7>	0 (unknown)

    • L/O refers to channel lock-out.
    • Not USED means that channel can not be unlocked from the keyboard unless a new frequency is programmed.
    • SECURE means that channel can not be altered from the keyboard.

    <band>; (1 byte):

    Bit(s)	Description
    <0>	IF shift: set to 1 for band 0, otherwise 0 for other bands
    <1>	set to 1 for 118–135.995, otherwise 0 (may be AM switch)
    <3:2>	0: 29 – 135.995 MHz (5 kHz spacing, 0.4 µV sensitivity) 1: 136 – 174 MHz (5 kHz spacing, 0.5 µV sensitivity) 2: 406 – 512 MHz (12.5 kHz spacing, 0.5 µV sensitivity) 3: 806 – 956 MHz (12.5 kHz spacing, 0.6 µV sensitivity)
    <4>	12.5 kHz decrement (range 806 – 956 MHz, see below)
    <7:5>	0 (unknown)

    <freq1>, <freq2>; (total 2 bytes):
    This is a 16 bit unsigned integer – most significant byte followed by least significant byte.

    This integer is calculated from the frequency. There are three different calculations depending on the band in which the frequency lies. ‘F’ represents the frequency in MHz.

    	band-byte				Theoretical Frequency Range
    F	<3:2>	<0>	Formula	Result Integer
    29 – 135.995	0	1	F × 200 + 2170	7970 – 29369	-10.85 – 316.8250
    136 – 174	1	0	F × 200 - 2170	25030 – 32630	10.85 – 338.5250
    406 – 512	2	0	F × 80 - 868	31612 – 40092	10.85 – 830.0375
    806 – 956 *	3	0		31806 – 37806	10.85 – 1649.2250

    ^*For range 806 – 956 MHz perform the additional calculations with the result integer:

    1. If integer is odd – add 1 to it, set bit <4> of band byte.
    2. Divide the integer by 2 (always)

    Bands 0 and 1 are set in 5 kHz intervals.
    Bands 2 and 3 are set in 12.5 kHz intervals.
    Note: according to specifications, 10.85 MHz is an intermediate frequency.

  Where <0x>, <bc> and <Bb> are bytes containing the following nibbles (4 bits):

  • x – arbitrary value
  • B – actual hex (11 decimal)
  • b – bank number 1 to 10 (1 – A hex)
  • c – channel number 1 to 10 (1 – A hex)
• <text>; (14 bytes)…

  16 ASCII characters are “compressed” to 14 data bytes. This is possible because only 7 out of 8 bits per byte are used (value 0 to 127). Because the high bit <7> is always 0 (unused) the bytes are left-shifted. The vacated least significant bit <0> is then used to squeeze in an extra character longitudenally. In summary:

  1. Characters 0 – 6 shift left by 1
  2. Vacated bit <0> of these characters is transposed character 7: bits <6> to <0> respectively
  3. Characters 8 – 14 shift left by 1
  4. Vacated bit <0> of these characters is transposed character 15: bits <6> to <0> respectively

  Allowable characters in text are ASCII in the range 32 to 127, with the following exceptions:

  Character	Decimal	Displayed as
  \	92	¥ (yen)
  ~	126	(right arrow)
  (del)	127	(left arrow)

  There are no descenders for the letters: g, j, p, q, y. They do not display well.

After sending data to the radio, unlock it (continue scanning) by sending a 0 byte.

NOTE: Data can not be sent to the radio if it happens to be locked on to the priority channel. Make sure the Priority indicator is off (press ‘PRI’).