|
Okay, so requiring a checksum on a 232 string is redonkulous (these days) to begin with - but check THIS one out: <paraphrased> "Two-byte checksum. Calculate an XOR of every ODD byte in the message (b1 XOR b3 XOR b5, etc) and invert the result - this is your first checksum byte. Now calculate an XOR of every EVEN byte in the message (b2 XOR b4 XOR b6, etc) and invert the result to obtain the second checksum byte" Really? Really?!?! - Chip
|
LOL - no SIMPL+ allowed for this :).
toggle quoted message
Show quoted text
On Thu, Apr 19, 2012 at 1:30 PM, Chip <cfm@...> wrote: **
Okay, so requiring a checksum on a 232 string is redonkulous (these days)
to begin with - but check THIS one out:
<paraphrased>
"Two-byte checksum. Calculate an XOR of every ODD byte in the message (b1
XOR b3 XOR b5, etc) and invert the result - this is your first checksum
byte. Now calculate an XOR of every EVEN byte in the message (b2 XOR b4 XOR
b6, etc) and invert the result to obtain the second checksum byte"
Really? Really?!?!
- Chip
|
That would be an intriguing challenge... :)
I only need five short commands - I calculated the checksums by hand...
- Chip
toggle quoted message
Show quoted text
--- In Crestron@..., Geoffrey Reynolds <greynlds@...> wrote:
LOL - no SIMPL+ allowed for this :).
On Thu, Apr 19, 2012 at 1:30 PM, Chip <cfm@...> wrote:
**
Okay, so requiring a checksum on a 232 string is redonkulous (these days)
to begin with - but check THIS one out:
<paraphrased>
"Two-byte checksum. Calculate an XOR of every ODD byte in the message (b1
XOR b3 XOR b5, etc) and invert the result - this is your first checksum
byte. Now calculate an XOR of every EVEN byte in the message (b2 XOR b4 XOR
b6, etc) and invert the result to obtain the second checksum byte"
Really? Really?!?!
- Chip
|
use an AnalogToSerial (ATOS) with format 666d
mb
toggle quoted message
Show quoted text
--- In Crestron@..., "Chip" <cfm@...> wrote:
That would be an intriguing challenge... :)
I only need five short commands - I calculated the checksums by hand...
- Chip
--- In Crestron@..., Geoffrey Reynolds <greynlds@> wrote:
LOL - no SIMPL+ allowed for this :).
On Thu, Apr 19, 2012 at 1:30 PM, Chip <cfm@> wrote:
**
Okay, so requiring a checksum on a 232 string is redonkulous (these days)
to begin with - but check THIS one out:
<paraphrased>
"Two-byte checksum. Calculate an XOR of every ODD byte in the message (b1
XOR b3 XOR b5, etc) and invert the result - this is your first checksum
byte. Now calculate an XOR of every EVEN byte in the message (b2 XOR b4 XOR
b6, etc) and invert the result to obtain the second checksum byte"
Really? Really?!?!
- Chip
[Non-text portions of this message have been removed]
|
I feel like I've faced this recently. Is this a lighting interface? I did the calcs by hand too.
toggle quoted message
Show quoted text
--- In Crestron@..., "Chip" <cfm@...> wrote:
Okay, so requiring a checksum on a 232 string is redonkulous (these days) to begin with - but check THIS one out:
<paraphrased>
"Two-byte checksum. Calculate an XOR of every ODD byte in the message (b1 XOR b3 XOR b5, etc) and invert the result - this is your first checksum byte. Now calculate an XOR of every EVEN byte in the message (b2 XOR b4 XOR b6, etc) and invert the result to obtain the second checksum byte"
Really? Really?!?!
- Chip
|
Silly Chip, They just want to make really really sure that the string is right.
They could have made it worse though.
Check3 = (Check2 Xor Check1)/Check4
Check4 = Inverted XOR of Whole string (including Check 1 - 3)
I am guessing security interface by the weird check-sums
toggle quoted message
Show quoted text
--- In Crestron@..., "Chip" <cfm@...> wrote:
That would be an intriguing challenge... :)
I only need five short commands - I calculated the checksums by hand...
- Chip
--- In Crestron@..., Geoffrey Reynolds <greynlds@> wrote:
LOL - no SIMPL+ allowed for this :).
On Thu, Apr 19, 2012 at 1:30 PM, Chip <cfm@> wrote:
**
Okay, so requiring a checksum on a 232 string is redonkulous (these days)
to begin with - but check THIS one out:
<paraphrased>
"Two-byte checksum. Calculate an XOR of every ODD byte in the message (b1
XOR b3 XOR b5, etc) and invert the result - this is your first checksum
byte. Now calculate an XOR of every EVEN byte in the message (b2 XOR b4 XOR
b6, etc) and invert the result to obtain the second checksum byte"
Really? Really?!?!
- Chip
[Non-text portions of this message have been removed]
|
You forgot the ":P" imho...
JRW
toggle quoted message
Show quoted text
--- In Crestron@..., "Witmarquzot" <tdurrant420@...> wrote:
Silly Chip, They just want to make really really sure that the string is right.
They could have made it worse though.
Check3 = (Check2 Xor Check1)/Check4
Check4 = Inverted XOR of Whole string (including Check 1 - 3)
I am guessing security interface by the weird check-sums
--- In Crestron@..., "Chip" <cfm@> wrote:
That would be an intriguing challenge... :)
I only need five short commands - I calculated the checksums by hand...
- Chip
--- In Crestron@..., Geoffrey Reynolds <greynlds@> wrote:
LOL - no SIMPL+ allowed for this :).
On Thu, Apr 19, 2012 at 1:30 PM, Chip <cfm@> wrote:
**
Okay, so requiring a checksum on a 232 string is redonkulous (these days)
to begin with - but check THIS one out:
<paraphrased>
"Two-byte checksum. Calculate an XOR of every ODD byte in the message (b1
XOR b3 XOR b5, etc) and invert the result - this is your first checksum
byte. Now calculate an XOR of every EVEN byte in the message (b2 XOR b4 XOR
b6, etc) and invert the result to obtain the second checksum byte"
Really? Really?!?!
- Chip
|
what was the device?
Stephen D.
toggle quoted message
Show quoted text
--- In Crestron@..., "Chip" <cfm@...> wrote:
That would be an intriguing challenge... :)
I only need five short commands - I calculated the checksums by hand...
- Chip
--- In Crestron@..., Geoffrey Reynolds <greynlds@> wrote:
LOL - no SIMPL+ allowed for this :).
On Thu, Apr 19, 2012 at 1:30 PM, Chip <cfm@> wrote:
**
Okay, so requiring a checksum on a 232 string is redonkulous (these days)
to begin with - but check THIS one out:
<paraphrased>
"Two-byte checksum. Calculate an XOR of every ODD byte in the message (b1
XOR b3 XOR b5, etc) and invert the result - this is your first checksum
byte. Now calculate an XOR of every EVEN byte in the message (b2 XOR b4 XOR
b6, etc) and invert the result to obtain the second checksum byte"
Really? Really?!?!
- Chip
[Non-text portions of this message have been removed]
|
Might not be this, but here's a device I recently came across that used the same scheme.
toggle quoted message
Show quoted text
--- In Crestron@..., "stainbow1" <stainbow1@...> wrote:
what was the device?
Stephen D.
--- In Crestron@..., "Chip" <cfm@> wrote:
That would be an intriguing challenge... :)
I only need five short commands - I calculated the checksums by hand...
- Chip
--- In Crestron@..., Geoffrey Reynolds <greynlds@> wrote:
LOL - no SIMPL+ allowed for this :).
On Thu, Apr 19, 2012 at 1:30 PM, Chip <cfm@> wrote:
**
Okay, so requiring a checksum on a 232 string is redonkulous (these days)
to begin with - but check THIS one out:
<paraphrased>
"Two-byte checksum. Calculate an XOR of every ODD byte in the message (b1
XOR b3 XOR b5, etc) and invert the result - this is your first checksum
byte. Now calculate an XOR of every EVEN byte in the message (b2 XOR b4 XOR
b6, etc) and invert the result to obtain the second checksum byte"
Really? Really?!?!
- Chip
|
Yes - good call!!
- Chip
toggle quoted message
Show quoted text
--- In Crestron@..., "josephporter2020" <ttbtssav@...> wrote:
I feel like I've faced this recently. Is this a lighting interface? I did the calcs by hand too.
--- In Crestron@..., "Chip" <cfm@> wrote:
Okay, so requiring a checksum on a 232 string is redonkulous (these days) to begin with - but check THIS one out:
<paraphrased>
"Two-byte checksum. Calculate an XOR of every ODD byte in the message (b1 XOR b3 XOR b5, etc) and invert the result - this is your first checksum byte. Now calculate an XOR of every EVEN byte in the message (b2 XOR b4 XOR b6, etc) and invert the result to obtain the second checksum byte"
Really? Really?!?!
- Chip
|
:D
I'll try to save some headache for you. If you are polling for feedback, you'll find that when you recall a preset, the actual lighting panel buttons will show feedback properly, but if the user recalls a preset from the lighting panel, the rs-232 interface does not reflect that change.
toggle quoted message
Show quoted text
--- In Crestron@..., "Chip" <cfm@...> wrote:
Yes - good call!!
- Chip
--- In Crestron@..., "josephporter2020" <ttbtssav@> wrote:
I feel like I've faced this recently. Is this a lighting interface? I did the calcs by hand too.
--- In Crestron@..., "Chip" <cfm@> wrote:
Okay, so requiring a checksum on a 232 string is redonkulous (these days) to begin with - but check THIS one out:
<paraphrased>
"Two-byte checksum. Calculate an XOR of every ODD byte in the message (b1 XOR b3 XOR b5, etc) and invert the result - this is your first checksum byte. Now calculate an XOR of every EVEN byte in the message (b2 XOR b4 XOR b6, etc) and invert the result to obtain the second checksum byte"
Really? Really?!?!
- Chip
|
Wow! That is tremendously stupid. You would think you were sending gps coordinates to a nuclear missile, not turning a light on and off.
I've seen some strange protocols/cksum calcs in my day, and this one ranks up with the **best**.
toggle quoted message
Show quoted text
--- In Crestron@..., "josephporter2020" <ttbtssav@...> wrote:
Might not be this, but here's a device I recently came across that used the same scheme.
--- In Crestron@..., "stainbow1" <stainbow1@> wrote:
what was the device?
Stephen D.
--- In Crestron@..., "Chip" <cfm@> wrote:
That would be an intriguing challenge... :)
I only need five short commands - I calculated the checksums by hand...
- Chip
--- In Crestron@..., Geoffrey Reynolds <greynlds@> wrote:
LOL - no SIMPL+ allowed for this :).
On Thu, Apr 19, 2012 at 1:30 PM, Chip <cfm@> wrote:
**
Okay, so requiring a checksum on a 232 string is redonkulous (these days)
to begin with - but check THIS one out:
<paraphrased>
"Two-byte checksum. Calculate an XOR of every ODD byte in the message (b1
XOR b3 XOR b5, etc) and invert the result - this is your first checksum
byte. Now calculate an XOR of every EVEN byte in the message (b2 XOR b4 XOR
b6, etc) and invert the result to obtain the second checksum byte"
Really? Really?!?!
- Chip
[Non-text portions of this message have been removed]
|
Fun! No, I'm neither polling nor planning on even interlocking the feedback on the touch panel light controls, as I gathered as much from the protocol docs! :)
- Chip
toggle quoted message
Show quoted text
--- In Crestron@..., "josephporter2020" <ttbtssav@...> wrote:
:D
I'll try to save some headache for you. If you are polling for feedback, you'll find that when you recall a preset, the actual lighting panel buttons will show feedback properly, but if the user recalls a preset from the lighting panel, the rs-232 interface does not reflect that change.
--- In Crestron@..., "Chip" <cfm@> wrote:
Yes - good call!!
- Chip
--- In Crestron@..., "josephporter2020" <ttbtssav@> wrote:
I feel like I've faced this recently. Is this a lighting interface? I did the calcs by hand too.
--- In Crestron@..., "Chip" <cfm@> wrote:
Okay, so requiring a checksum on a 232 string is redonkulous (these days) to begin with - but check THIS one out:
<paraphrased>
"Two-byte checksum. Calculate an XOR of every ODD byte in the message (b1 XOR b3 XOR b5, etc) and invert the result - this is your first checksum byte. Now calculate an XOR of every EVEN byte in the message (b2 XOR b4 XOR b6, etc) and invert the result to obtain the second checksum byte"
Really? Really?!?!
- Chip
|
I vote that we hunt down the engineer(s) that created this kind of misery, and make a stern example of him that there would be fear in the hearts of all other protocol writers ...
Huzzah!! Who's with me???
Chris K..............;)
toggle quoted message
Show quoted text
--- In Crestron@..., "erikm_101" <erikm101@...> wrote:
Wow! That is tremendously stupid. You would think you were sending gps coordinates to a nuclear missile, not turning a light on and off.
I've seen some strange protocols/cksum calcs in my day, and this one ranks up with the **best**.
--- In Crestron@..., "josephporter2020" <ttbtssav@> wrote:
Might not be this, but here's a device I recently came across that used the same scheme.
--- In Crestron@..., "stainbow1" <stainbow1@> wrote:
what was the device?
Stephen D.
--- In Crestron@..., "Chip" <cfm@> wrote:
That would be an intriguing challenge... :)
I only need five short commands - I calculated the checksums by hand...
- Chip
--- In Crestron@..., Geoffrey Reynolds <greynlds@> wrote:
LOL - no SIMPL+ allowed for this :).
On Thu, Apr 19, 2012 at 1:30 PM, Chip <cfm@> wrote:
**
Okay, so requiring a checksum on a 232 string is redonkulous (these days)
to begin with - but check THIS one out:
<paraphrased>
"Two-byte checksum. Calculate an XOR of every ODD byte in the message (b1
XOR b3 XOR b5, etc) and invert the result - this is your first checksum
byte. Now calculate an XOR of every EVEN byte in the message (b2 XOR b4 XOR
b6, etc) and invert the result to obtain the second checksum byte"
Really? Really?!?!
- Chip
|
Amen. Almost anything with a checksum is silly in my book.
They must be bullied math nerds getting back at the programmers who picked on them in college. Thinking, "they'll need to know group theory to use my protocol."
Heath Volmer
Digital Domain Systems
(303) 517-9714
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Show quoted text
On Apr 20, 2012, at 2:10 PM, ChrisK wrote: I vote that we hunt down the engineer(s) that created this kind of misery, and make a stern example of him that there would be fear in the hearts of all other protocol writers ...
Huzzah!! Who's with me???
Chris K..............;)
--- In Crestron@..., "erikm_101" <erikm101@...> wrote:
Wow! That is tremendously stupid. You would think you were sending gps coordinates to a nuclear missile, not turning a light on and off.
I've seen some strange protocols/cksum calcs in my day, and this one ranks up with the **best**.
--- In Crestron@..., "josephporter2020" <ttbtssav@> wrote:
Might not be this, but here's a device I recently came across that used the same scheme.
--- In Crestron@..., "stainbow1" <stainbow1@> wrote:
what was the device?
Stephen D.
--- In Crestron@..., "Chip" <cfm@> wrote:
That would be an intriguing challenge... :)
I only need five short commands - I calculated the checksums by hand...
- Chip
--- In Crestron@..., Geoffrey Reynolds <greynlds@> wrote:
LOL - no SIMPL+ allowed for this :).
On Thu, Apr 19, 2012 at 1:30 PM, Chip <cfm@> wrote:
**
Okay, so requiring a checksum on a 232 string is redonkulous (these days)
to begin with - but check THIS one out:
<paraphrased>
"Two-byte checksum. Calculate an XOR of every ODD byte in the message (b1
XOR b3 XOR b5, etc) and invert the result - this is your first checksum
byte. Now calculate an XOR of every EVEN byte in the message (b2 XOR b4 XOR
b6, etc) and invert the result to obtain the second checksum byte"
Really? Really?!?!
- Chip
[Non-text portions of this message have been removed]
|
I've got my brass knuckles and baseball bat. Just tell me where and when.
While we're at it can we beat on protocol engineers who's devices respond
with "OK\x0D" to a command to select input 96 to output 128? AAAARRRRGHHH
toggle quoted message
Show quoted text
On Fri, Apr 20, 2012 at 2:10 PM, ChrisK <chris@...> wrote: **
I vote that we hunt down the engineer(s) that created this kind of misery,
and make a stern example of him that there would be fear in the hearts of
all other protocol writers ...
Huzzah!! Who's with me???
Chris K..............;)
--- In Crestron@..., "erikm_101" <erikm101@...> wrote:
Wow! That is tremendously stupid. You would think you were sending gps
coordinates to a nuclear missile, not turning a light on and off.
I've seen some strange protocols/cksum calcs in my day, and this one
ranks up with the **best**.
--- In Crestron@..., "josephporter2020" <ttbtssav@> wrote:
Might not be this, but here's a device I recently came across that
used the same scheme.
--- In Crestron@..., "stainbow1" <stainbow1@> wrote:
what was the device?
Stephen D.
--- In Crestron@..., "Chip" <cfm@> wrote:
That would be an intriguing challenge... :)
I only need five short commands - I calculated the checksums by
hand...
- Chip
--- In Crestron@..., Geoffrey Reynolds <greynlds@>
wrote:
LOL - no SIMPL+ allowed for this :).
On Thu, Apr 19, 2012 at 1:30 PM, Chip <cfm@> wrote:
**
Okay, so requiring a checksum on a 232 string is redonkulous
(these days)
to begin with - but check THIS one out:
<paraphrased>
"Two-byte checksum. Calculate an XOR of every ODD byte in the
message (b1
XOR b3 XOR b5, etc) and invert the result - this is your first
checksum
byte. Now calculate an XOR of every EVEN byte in the message
(b2 XOR b4 XOR
b6, etc) and invert the result to obtain the second checksum
byte"
Really? Really?!?!
- Chip
[Non-text portions of this message have been removed]
|
Or boxes that respond to a query command with >only< an integer value of the result (Extron, Sharp, and Sanyo...I'm talking about you!).
Tx: "Input,2=?\r"
Rx: "4\r"
Stupid, stupid, stupid.
toggle quoted message
Show quoted text
On 4/20/2012 4:22 PM, Neil Dorin wrote: I've got my brass knuckles and baseball bat. Just tell me where and when.
While we're at it can we beat on protocol engineers who's devices respond
with "OK\x0D" to a command to select input 96 to output 128? AAAARRRRGHHH
On Fri, Apr 20, 2012 at 2:10 PM, ChrisK<chris@...> wrote:
**
I vote that we hunt down the engineer(s) that created this kind of misery,
and make a stern example of him that there would be fear in the hearts of
all other protocol writers ...
Huzzah!! Who's with me???
Chris K..............;)
--- In Crestron@..., "erikm_101"<erikm101@...> wrote:
Wow! That is tremendously stupid. You would think you were sending gps coordinates to a nuclear missile, not turning a light on and off.
I've seen some strange protocols/cksum calcs in my day, and this one ranks up with the **best**.
--- In Crestron@..., "josephporter2020"<ttbtssav@> wrote:
Might not be this, but here's a device I recently came across that used the same scheme.
--- In Crestron@..., "stainbow1"<stainbow1@> wrote:
what was the device?
Stephen D.
--- In Crestron@..., "Chip"<cfm@> wrote:
That would be an intriguing challenge... :)
I only need five short commands - I calculated the checksums by
hand...
- Chip
--- In Crestron@..., Geoffrey Reynolds<greynlds@>
wrote:
LOL - no SIMPL+ allowed for this :).
On Thu, Apr 19, 2012 at 1:30 PM, Chip<cfm@> wrote:
**
Okay, so requiring a checksum on a 232 string is redonkulous
(these days)
to begin with - but check THIS one out:
<paraphrased>
"Two-byte checksum. Calculate an XOR of every ODD byte in the
message (b1
XOR b3 XOR b5, etc) and invert the result - this is your first
checksum
byte. Now calculate an XOR of every EVEN byte in the message
(b2 XOR b4 XOR
b6, etc) and invert the result to obtain the second checksum
byte"
Really? Really?!?!
- Chip
------------------------------------
Check out the Files area for useful modules, documents, and drivers.
A contact list of Crestron dealers and programmers can be found in the Database area.
Yahoo! Groups Links
|
Anyone up for a protocol bonfire at Infocomm? We can through both the docs and the engineers to blame in...
With the Extron party being out, everyone has a free night, right? ;-)
--
Lincoln King-Cliby, CTS
Sr. Systems Architect | Crestron Certified Programmer (Silver)
ControlWorks Consulting, LLC
V: 440.449.1100 x1107 | F: 440.449.1106 | I:
Crestron Authorized Independent Programmer
toggle quoted message
Show quoted text
-----Original Message----- From: Crestron@... [mailto:Crestron@...] On Behalf Of ChrisK Sent: Friday, April 20, 2012 4:11 PM To: Crestron@... Subject: [Crestron] Re: Protocol rant... I vote that we hunt down the engineer(s) that created this kind of misery, and make a stern example of him that there would be fear in the hearts of all other protocol writers ... Huzzah!! Who's with me??? Chris K..............;) --- In Crestron@..., "erikm_101" <erikm101@...> wrote:
Wow! That is tremendously stupid. You would think you were sending gps coordinates to a nuclear missile, not turning a light on and off.
I've seen some strange protocols/cksum calcs in my day, and this one ranks up with the **best**.
--- In Crestron@..., "josephporter2020" <ttbtssav@> wrote:
Might not be this, but here's a device I recently came across that used the same scheme.
--- In Crestron@..., "stainbow1" <stainbow1@> wrote:
what was the device?
Stephen D.
--- In Crestron@..., "Chip" <cfm@> wrote:
That would be an intriguing challenge... :)
I only need five short commands - I calculated the checksums by hand...
- Chip
--- In Crestron@..., Geoffrey Reynolds <greynlds@> wrote:
LOL - no SIMPL+ allowed for this :).
On Thu, Apr 19, 2012 at 1:30 PM, Chip <cfm@> wrote:
**
Okay, so requiring a checksum on a 232 string is redonkulous (these days)
to begin with - but check THIS one out:
<paraphrased>
"Two-byte checksum. Calculate an XOR of every ODD byte in the message (b1
XOR b3 XOR b5, etc) and invert the result - this is your first checksum
byte. Now calculate an XOR of every EVEN byte in the message (b2 XOR b4 XOR
b6, etc) and invert the result to obtain the second checksum byte"
Really? Really?!?!
- Chip
[Non-text portions of this message have been removed]
------------------------------------ Check out the Files area for useful modules, documents, and drivers. A contact list of Crestron dealers and programmers can be found in the Database area. Yahoo! Groups Links
|
The checksum is pretty simple (and cheap/easy from a hardware perspective) -- it's the phrasing in manual that is extra stupid. Rephrase as: 0xFFFF xor Word1 xor Word2 .... WordN and it becomes less intimidating. If Crestron let us do bitwise math on analogs, it would be dead easy. On Fri, 20 Apr 2012 14:49:20 -0000, "erikm_101" <erikm101@...> wrote: Wow! That is tremendously stupid. You would think you were sending gps coordinates to a
nuclear missile, not turning a light on and off.
I've seen some strange protocols/cksum calcs in my day, and this one ranks up with the **best**.
--- In Crestron@..., "josephporter2020" <ttbtssav@...> wrote:
Might not be this, but here's a device I recently came across that used the same scheme.
--- In Crestron@..., "stainbow1" <stainbow1@> wrote:
what was the device?
Stephen D.
--- In Crestron@..., "Chip" <cfm@> wrote:
That would be an intriguing challenge... :)
I only need five short commands - I calculated the checksums by hand...
- Chip
--- In Crestron@..., Geoffrey Reynolds <greynlds@> wrote:
LOL - no SIMPL+ allowed for this :).
On Thu, Apr 19, 2012 at 1:30 PM, Chip <cfm@> wrote:
**
Okay, so requiring a checksum on a 232 string is redonkulous (these days)
to begin with - but check THIS one out:
<paraphrased>
"Two-byte checksum. Calculate an XOR of every ODD byte in the message (b1
XOR b3 XOR b5, etc) and invert the result - this is your first checksum
byte. Now calculate an XOR of every EVEN byte in the message (b2 XOR b4 XOR
b6, etc) and invert the result to obtain the second checksum byte"
Really? Really?!?!
- Chip
|
Easy, perhaps....but is it necessary? For turning on a light? C'mon, how bout just NAK a message you don't like and get over it?
toggle quoted message
Show quoted text
--- In Crestron@..., Kool-Aid Drinker <crug@...> wrote:
The checksum is pretty simple (and cheap/easy from a hardware
perspective) -- it's the phrasing in manual that is extra stupid.
Rephrase as:
0xFFFF xor Word1 xor Word2 .... WordN
and it becomes less intimidating.
If Crestron let us do bitwise math on analogs, it would be dead easy.
On Fri, 20 Apr 2012 14:49:20 -0000, "erikm_101" <erikm101@...>
wrote:
Wow! That is tremendously stupid. You would think you were sending gps coordinates to a
nuclear missile, not turning a light on and off.
I've seen some strange protocols/cksum calcs in my day, and this one ranks up with the **best**.
--- In Crestron@..., "josephporter2020" <ttbtssav@> wrote:
Might not be this, but here's a device I recently came across that used the same scheme.
--- In Crestron@..., "stainbow1" <stainbow1@> wrote:
what was the device?
Stephen D.
--- In Crestron@..., "Chip" <cfm@> wrote:
That would be an intriguing challenge... :)
I only need five short commands - I calculated the checksums by hand...
- Chip
--- In Crestron@..., Geoffrey Reynolds <greynlds@> wrote:
LOL - no SIMPL+ allowed for this :).
On Thu, Apr 19, 2012 at 1:30 PM, Chip <cfm@> wrote:
**
Okay, so requiring a checksum on a 232 string is redonkulous (these days)
to begin with - but check THIS one out:
<paraphrased>
"Two-byte checksum. Calculate an XOR of every ODD byte in the message (b1
XOR b3 XOR b5, etc) and invert the result - this is your first checksum
byte. Now calculate an XOR of every EVEN byte in the message (b2 XOR b4 XOR
b6, etc) and invert the result to obtain the second checksum byte"
Really? Really?!?!
- Chip
|
Michael Block