Difference between revisions of "Telephone system:Cisco PoE hack"
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| + | === synopsis === | ||
Inspired from info at [http://www.voip-info.org/wiki/view/Cisco+POE voip-info.org], found it confusing, so I started testing myself.. | Inspired from info at [http://www.voip-info.org/wiki/view/Cisco+POE voip-info.org], found it confusing, so I started testing myself.. | ||
| − | + | This part gives some quick information on converting/applying 802.3af PoE for usage on the 79x0 series pre-standard PoE <abbr title="Powered Device">PD</abbr>s. | |
| − | * [http://www.netgear.com/business/products/switches/smart | + | |
| + | For a type B <abbr title="Power Sources Equipment">PSE</abbr> uses the spare pairs (4,5 and 7,8) with being 802.3af: undetermined polarity. | ||
| + | Test power by placing a 25kohm resistor between pins 4 and 7. | ||
| + | Now, make sure the pins 4 and 5 contain the positive (+48) voltage, while pins 7 and 8 have the negative (GND) voltage. | ||
| + | You might need to swap pairs 4+5 with 7+8 (blue with brown) | ||
| + | |||
| + | For a type A PSE (like NetGear FS108P), make sure the switch supports <abbr title="also known as 'auto-MDIX'">auto-sensing MDI/MDIX</abbr> | ||
| + | Test power by placing a 25kohm resistor between pins 1 and 3. | ||
| + | Grab a crossover cable and make sure the voltage polarity is correct. | ||
| + | |||
| + | === the stuff tested === | ||
| + | * [http://www.netgear.com/business/products/switches/smart/GS110TP.aspx Netgear GS110TP] which turned out to be 802.3af type A (power on the data pairs) | ||
* Cisco CP-7940 and CP-7960: known to be pre-standard PoE. | * Cisco CP-7940 and CP-7960: known to be pre-standard PoE. | ||
* 22k resistor | * 22k resistor | ||
| + | === what you need to do to build one === | ||
* Build an adapter cable that has a regular connector wired type B, and an outlet with the cables crimped on it the same (regular 'extension' cable, but can be very short) | * Build an adapter cable that has a regular connector wired type B, and an outlet with the cables crimped on it the same (regular 'extension' cable, but can be very short) | ||
* undo the outlet's cap carefully, keeping the wires in place | * undo the outlet's cap carefully, keeping the wires in place | ||
| − | * use S-39 on the 'forks' for pin 1 and 3 (white-orange and white-green).<br/>careful that you have the ordering correct: outlets order pins by color pairs.<br/>the S-39 is for the forks to quickly get tinned without destroying the insulation | + | * use [http://nl.wikipedia.org/wiki/S-39 S-39] on the 'forks' for pin 1 and 3 (white-orange and white-green).<br/>careful that you have the ordering correct: outlets order pins by color pairs.<br/>the S-39 is for the forks to quickly get tinned without destroying the insulation |
* be sure the leads of the resistor are slightly shortened, so that it will just pop out of the outlet at the back. | * be sure the leads of the resistor are slightly shortened, so that it will just pop out of the outlet at the back. | ||
* solder it! | * solder it! | ||
* carefully place the cap back with the resistor leads joining the other wires | * carefully place the cap back with the resistor leads joining the other wires | ||
| + | === connecting it === | ||
Now, if you connect everything, '''the phone won't boot'''. It seems to be a kind of protection. | Now, if you connect everything, '''the phone won't boot'''. It seems to be a kind of protection. | ||
* leave the phone disconnected | * leave the phone disconnected | ||
| Line 19: | Line 33: | ||
* when the PoE led lights up, plug it in to the CP-79x0 phone's switch socket: it should get power and start the boot sequence | * when the PoE led lights up, plug it in to the CP-79x0 phone's switch socket: it should get power and start the boot sequence | ||
| − | === | + | === tests === |
| − | When it didn't work, I tried to make a [http://hardwarebook.info/Ethernet_10/100/1000Base-T_and_100Base-T4_Crossover cross cable] (at least I think I did, I have to verify), but that didn't seem to work either: it triggered power, but the phone did nothing (probably thanks to a reversed polarity protection diode). | + | When at first it didn't work, I tried to make a [http://hardwarebook.info/Ethernet_10/100/1000Base-T_and_100Base-T4_Crossover cross cable] (at least I think I did, I have to verify the spare pair ordering), but that didn't seem to work either: it triggered power on the switch, but the phone did nothing (probably thanks to a reversed polarity protection diode). |
Then, when I plugged in the straight cable without phone, it booted; so I took a gamble and plugged the powered rj45, and it worked. | Then, when I plugged in the straight cable without phone, it booted; so I took a gamble and plugged the powered rj45, and it worked. | ||
| − | After testing, the actual network seems to work fine | + | After testing, the actual network seems to work fine (tested with 3m cable) |
| + | [[Category:Telephony]][[Category:PoE]] | ||
Latest revision as of 09:46, 14 January 2022
synopsis
Inspired from info at voip-info.org, found it confusing, so I started testing myself..
This part gives some quick information on converting/applying 802.3af PoE for usage on the 79x0 series pre-standard PoE PDs.
For a type B PSE uses the spare pairs (4,5 and 7,8) with being 802.3af: undetermined polarity. Test power by placing a 25kohm resistor between pins 4 and 7. Now, make sure the pins 4 and 5 contain the positive (+48) voltage, while pins 7 and 8 have the negative (GND) voltage. You might need to swap pairs 4+5 with 7+8 (blue with brown)
For a type A PSE (like NetGear FS108P), make sure the switch supports auto-sensing MDI/MDIX Test power by placing a 25kohm resistor between pins 1 and 3. Grab a crossover cable and make sure the voltage polarity is correct.
the stuff tested
- Netgear GS110TP which turned out to be 802.3af type A (power on the data pairs)
- Cisco CP-7940 and CP-7960: known to be pre-standard PoE.
- 22k resistor
what you need to do to build one
- Build an adapter cable that has a regular connector wired type B, and an outlet with the cables crimped on it the same (regular 'extension' cable, but can be very short)
- undo the outlet's cap carefully, keeping the wires in place
- use S-39 on the 'forks' for pin 1 and 3 (white-orange and white-green).
careful that you have the ordering correct: outlets order pins by color pairs.
the S-39 is for the forks to quickly get tinned without destroying the insulation - be sure the leads of the resistor are slightly shortened, so that it will just pop out of the outlet at the back.
- solder it!
- carefully place the cap back with the resistor leads joining the other wires
connecting it
Now, if you connect everything, the phone won't boot. It seems to be a kind of protection.
- leave the phone disconnected
- connect a regular network cable to the switch of your desired length
- connect the adapter's outlet to the cable and wait (at most 5 seconds)
- when the PoE led lights up, plug it in to the CP-79x0 phone's switch socket: it should get power and start the boot sequence
tests
When at first it didn't work, I tried to make a cross cable (at least I think I did, I have to verify the spare pair ordering), but that didn't seem to work either: it triggered power on the switch, but the phone did nothing (probably thanks to a reversed polarity protection diode).
Then, when I plugged in the straight cable without phone, it booted; so I took a gamble and plugged the powered rj45, and it worked.
After testing, the actual network seems to work fine (tested with 3m cable)
