KY-04 RS232 specifications

Notice that, on a windows-based machine, all RS-232 functionality of the KY-04 will also be available using the Key4win program.

RS-232 commands

Command	Description	Remarks
nxxxxxx<cr>	New key. xxxxxx is the six-character hexadecimal code of the key, the last 6 characters of the laser-etched number on the key itself. KY-04 confirms addition with an exclamation mark ('!'), or alternatively prints 'F' if the non-volatile memory page is full.
dxxxxxx<cr>	Delete key. xxxxxx is the six-character hexadecimal code of the key, the last 6 characters of the laser-etched number on the key itself. KY-04 confirms deletion with an exclamation mark ('!'), or alternatively prints '?' if the key was not found in the non-volatile memory.
s	Show all keys in non-volatile memory: one key per line, 6 hexadecimal characters per key.
c!	Clear all keys from non-volatile memory, including the master key. The first key held to a contact becomes the new master (The subsequent initialization of the non-volatile memory can take up to 8 seconds).	The exclamation mark should be sent within 2 seconds after the 'c'.
o	Open lock A for 2 seconds.
b	Open lock B for 2 seconds.
r	Reset: restarts the system, closes locks A and B, and resets the waiting time incurred for unknown keys.
h!	Host mode. After this command all information is still passed over RS-232, but the locks will not be opened by the KY-04 itself. This can still be done using the 'o' and 'b' commands. Host mode can only be ended by issuing the reset command. A system without functioning non-volatile memory automatically starts in host mode.	The exclamation mark should be sent within 2 seconds after the 'h'.

RS-232 output specifications

1. Reset

1.1 Version for 24C16 Eeprom:

1.2 Version for 24C64 Eeprom:

2. Prompt

2.1 Version with silicon serial number

"xxxxxxxx " where x is a hexadecimal digit

2.2 Version without silicon serial number:

"IDD "

3. Key held to contact

"<01.XXXXXXxxxxxx.xx"
  || |||||||||||| ++-- CRC checksum byte
  || ||||||++++++----- Number of the key, only lower 24 bits are significant
  || ++++++----------- Upper 24 bits, disregarded
  ++------------------ Device code, is 01 for standard Dallas keys

The following will then be output (pseudo code):

  switch (CRC) {
    case CRC_OK:  "+"   Indicate valid CRC checksum
                  if (not in host mode) {
                    if (Eeprom primed) {
                      switch(key) {
                        case master:   "M"   Indicate master key
                                       ">O"  Open lock (for 2 seconds)
                                       if (master key for 10 seconds)
                                         "R"   Eeprom is being "reset" (blanked)
                                         "W"   Wait (for 2 seconds)
                                         ">O"  Open lock (for 0.5 second)
                                      else if (add key)
                                         "N"   Add new key
                                         if (Eeprom full)
                                           "F"   Indicate Eeprom full
                                       else if (delete key)
                                         "D"   Delete key
                                       }

                        case known:    "K"   Indicate known key
                                       if (master before us recently)
                                         "x"   Indicate key might be deleted
                                         ">C"  Close lock
                                       else
                                         ">O"  Open lock (for 2 seconds)
                                       }

                        case unknown:  "U"   Indicate unknown key
                                       if (master before us recently)
                                         "x"   Indicate key might be added
                                         ">C"  Close lock
                                       else
                                         if (same unknown as previous)
                                           "="   Indicate same unknown
                                         else
                                           "W"   Indicate contact blocked for some time (Waiting)
                                         }
                                       }
                      }

                    else {
                      "PW8"   Initialising ("programming") the Eeprom
                      ">O"    Open lock (for half a second)
                    }
                  }

    case CRC_BAD:  "-"   Indicate invalid CRC checksum
  }

  if (this was contact B) {
    "B"
  }
  "<cr><lf>"
  New prompt

4. Lock closes

  ">C"
  if (this was lock B) {
    "B"
  }
  New prompt

RS-232 examples

1. Key detected on contact B


0144a863 <01.00000112c9c7.62+K>OB 

0144a863 >CB 

0144a863

Explanation:

0144a863 The KY-04 prompt, in this case the serial number of the lock

< Indication of a key held to a contact

01.00000112c9c7.62 The family code of the key (01), the complete serial number of the key (00000112c9c7, of which only the last 6 characters (12c9c7) are significant), and the CRC checksum byte (62)

+ Indicates a positive Cyclic Redundancy Check (CRC)

K The key has been found in the non-volatile memory of the KY-04

> Indication of an action by the KY-04

O Indication that a lock was opened

B Indication that this key was held to contact B and that lock B was opened

0144a863 >CB Indication that lock B was closed (after 2 seconds)

0144a863 New prompt

2. Key added using master key on contact A

`0144a863 <01.00000112c9c7.62+M>O`	Master 12c9c7 detected (M), lock opened (>O)
`0144a863 <01.00000038674a.93+Ux>C`	Unknown key 38674a detected (U), within 2 seconds after master (x), lock closed (>C)
`0144a863 <01.00000112c9c7.62+M>ON`	Master 12c9c7 detected (M), lock opened (>O), new user key added (N)
`0144a863 >C`	Lock closed (>C) after half a second (acknowledge pulse)
`0144a863 <01.00000038674a.93+K>OB`	Known key 38674a detected on contact B, lock B opened
`0144a863 >CB`	Lock B closed after two seconds

Differences with KY-01/KY-03

KY-04 has two contacts that drive seperate relays. RS-232 messages regarding contact B are identical to those of contact A, except that they have a 'B' added as the last character on the line.
KY-04 will use 'IDD ' as a prompt if no external Dallas lock ID is connected.
KY-04 detects when a contact is being short-circuited and keeps sending the message '>S' for as long as this condition endures.
KY-04 is full-duplex. However, just like with the KY-01/03 you have to wait until the current RS-232 command is completely executed (indicated by a new prompt being output) before you should send the next command (Rule of thumb: when you receive the CR/LF of the new prompt, it's OK to start sending the new command).
KY-04 recognises hardware-handshaking (RTS/CTS).
KY-04 keeps running even if the device connected to it by RS-232 has issued a XOFF or has pulled CTS low. If the connected device doesn't resume input in time, it may lose information.
KY-04 keeps running even if the device connected to it by RS-232 is sending command-characters. This might lead to situations like this:

IDD n123<01.000001655ab2.62+>O
IDD 456!
IDD >C
IDD
Remark: this will not occur during the execution of a command (eg. during the dump of all keys in non-volatile memory).

KY-04 has a time penalty that climbs after each subsequent unknown key in the sequence 1-seconds-2 seconds-4 seconds-8 seconds-5 minutes. The penalty drops one level for every 5 minutes that no unknown keys were held to the contact. The penalty also drops one level whenever a valid (known) key is held to a contact which isn't blocked. Please note that although only the offending contact will be blocked, both contacts share the same penalty: if you hold four different unknown keys to contact A and then one unknown key to contact B, both contacts will be blocked for 5 minutes.
KY-04 has an internal watchdog timer.
KY-04 considers 00.000000000000.00 to have a bad CRC as a precaution, even though this is not actually true.
KY-04 has a more accurate ASCII->hexadecimal conversion, and as an added feature recognises 'O' as '0' and 'l' as '1'.
KY-04 doesn't support the alien output any more.
KY-04 demands that the "h"-command (Host mode) be confirmed with an exclamation mark ("!") as a precaution.
KY-04 will not mark an Eeprom that's being initialised as "Primed" until initialisation has been completed. This prevents Eeproms from being in an inconsistent state when initialisation was interrupted prematurely (eg. someone pulled the power cord out).
KY-04 exists in two versions, for either a 24C16 Eeprom (650+ keys) or a 24C64 Eeprom (2600+).
KY-04 is more precise in controlling its Eeprom, making Eeprom access 2 to 3 times faster and theoretically resulting in lower Eeprom wear.

The main KY-04 page.
The KY-04s wiring scheme.
The KY-04d wiring scheme.
The main KY-series page.

For more information please contact: contact@idd.nl

site by ii.nl

`0144a863`	The KY-04 prompt, in this case the serial number of the lock
`<`	Indication of a key held to a contact
`01.00000112c9c7.62`	The family code of the key (01), the complete serial number of the key (00000112c9c7, of which only the last 6 characters (12c9c7) are significant), and the CRC checksum byte (62)
`+`	Indicates a positive Cyclic Redundancy Check (CRC)
`K`	The key has been found in the non-volatile memory of the KY-04
`>`	Indication of an action by the KY-04
`O`	Indication that a lock was opened
`B`	Indication that this key was held to contact B and that lock B was opened
`0144a863 >CB`	Indication that lock B was closed (after 2 seconds)
`0144a863`	New prompt