RJ45 splitter for Ethernet - possible ?

happen to run across this thread over on the Ethernet newsgroup -

Some guy found a RJ45 splitter (2-RJ45 jacks to 1-RJ45 jack)
over on ebay (search RJ45 spliiter) that look like the telco 1-line 2-line
adapters,
but yet this guy (and the ebay description) says these "splitters" ....

Features:
a.. Convert a single RJ45 outlet to two RJ45 sockets easily, point for
more conveniently use

b.. Increase the number of RJ45 network connections on an RJ45 outlet

c.. Compact design, feel free to enjoy your internet surfing

d.. Expand one RJ 45 outlet into two 8 wire RJ-45 T adapter, parallel
wiring

e.. Connector: 3 x RJ45 female

f.. 100% Brand New.

It doesn't even seem possible to have more "network connections"
by just splicing more Ethernet wires together vs a dumb hub ????

I could see if you were trying to split out the tip/ring (4/5) or power
(7/8)
but an Ethernet splitter ?????

--
----------------------------------
"If everything seems to be going well,
you have obviously overlooked something." - Steven Wright

"P.Schuman" <(E-Mail Removed)> fired this volley in
news:Ry8Hj.36354$(E-Mail Removed). net:

> happen to run across this thread over on the Ethernet newsgroup -
>
> Some guy found a RJ45 splitter (2-RJ45 jacks to 1-RJ45 jack)
> over on ebay (search RJ45 spliiter) that look like the telco 1-line
> 2-line adapters,
> but yet this guy (and the ebay description) says these "splitters"
> ....
>
> Features:
> a.. Convert a single RJ45 outlet to two RJ45 sockets easily, point
> for
> more conveniently use
>
> b.. Increase the number of RJ45 network connections on an RJ45
> outlet
>
> c.. Compact design, feel free to enjoy your internet surfing
>
> d.. Expand one RJ 45 outlet into two 8 wire RJ-45 T adapter,
> parallel
> wiring
>
> e.. Connector: 3 x RJ45 female
>
> f.. 100% Brand New.
>
> It doesn't even seem possible to have more "network connections"
> by just splicing more Ethernet wires together vs a dumb hub ????
>
> I could see if you were trying to split out the tip/ring (4/5) or
> power (7/8)
> but an Ethernet splitter ?????
>

The advertiser did not say "Ethernet network connections", he said
"network connections". Telephone systems are called "networks", also.

However, his presumption that its compact size will somehow enhance your
internet experience is both stupid AND leads one to believe he thinks you
CAN tee an ethernet connection.

LLoyd

I've had splitters like this in my tool box for the past decade, but
have not actually implemented them.

Mine, are male on one side, and two female on the other.

Imagine that you plugged one into a wall jack at the location of a
workstation, and another in the closet where your switch resides.

This would support two Ethernet or FastEthernet devices at the
workstation location (e.g.: host, and network attached printer).

Each device would utilize two of the four pairs within the 8-wire (e.g.:
Cat 5e) cable.

This is however, not an appropriate thing to do from a performance
standpoint, and should not be standard practice.

If you were utilizing GigEthernet, I believe all four pairs are used to
support a single device, and therefore splitting would not be an option.


Best Regards,
News Reader

P.Schuman wrote:
> happen to run across this thread over on the Ethernet newsgroup -
>
> Some guy found a RJ45 splitter (2-RJ45 jacks to 1-RJ45 jack)
> over on ebay (search RJ45 spliiter) that look like the telco 1-line 2-line
> adapters,
> but yet this guy (and the ebay description) says these "splitters" ....
>
> Features:
> a.. Convert a single RJ45 outlet to two RJ45 sockets easily, point for
> more conveniently use
>
> b.. Increase the number of RJ45 network connections on an RJ45 outlet
>
> c.. Compact design, feel free to enjoy your internet surfing
>
> d.. Expand one RJ 45 outlet into two 8 wire RJ-45 T adapter, parallel
> wiring
>
> e.. Connector: 3 x RJ45 female
>
> f.. 100% Brand New.
>
> It doesn't even seem possible to have more "network connections"
> by just splicing more Ethernet wires together vs a dumb hub ????
>
> I could see if you were trying to split out the tip/ring (4/5) or power
> (7/8)
> but an Ethernet splitter ?????
>

News Reader wrote:
> I've had splitters like this in my tool box for the past decade, but
> have not actually implemented them.

ok - that pretty much answers the rest of your points

> Mine, are male on one side, and two female on the other.
>
> Imagine that you plugged one into a wall jack at the location of a
> workstation, and another in the closet where your switch resides.
>
> This would support two Ethernet or FastEthernet devices at the
> workstation location (e.g.: host, and network attached printer).

really - how ?

> Each device would utilize two of the four pairs within the 8-wire
> (e.g.: Cat 5e) cable.

really - how ?
considering that each Ethernet device normally expects pins 1/2 and 3/6
to be used ?
So, you would have to fabricate a custom cable for each of these
connections at each end
and then plug that cable into your cable-sharing RJ45 splitters..
1/2 = 1/2
3/6 = 3/4

1/2 = 5/6
3/6 = 7/8

> This is however, not an appropriate thing to do from a performance
> standpoint, and should not be standard practice.
>
> If you were utilizing GigEthernet, I believe all four pairs are used
> to support a single device, and therefore splitting would not be an
> option.
>
> Best Regards,
> News Reader
>
> P.Schuman wrote:
>> happen to run across this thread over on the Ethernet newsgroup -
>>
>> Some guy found a RJ45 splitter (2-RJ45 jacks to 1-RJ45 jack)
>> over on ebay (search RJ45 spliiter) that look like the telco 1-line
>> 2-line adapters,
>> but yet this guy (and the ebay description) says these "splitters"
>> .... Features:
>> a.. Convert a single RJ45 outlet to two RJ45 sockets easily, point
>> for more conveniently use
>>
>> b.. Increase the number of RJ45 network connections on an RJ45
>> outlet c.. Compact design, feel free to enjoy your internet surfing
>>
>> d.. Expand one RJ 45 outlet into two 8 wire RJ-45 T adapter,
>> parallel wiring
>>
>> e.. Connector: 3 x RJ45 female
>>
>> f.. 100% Brand New.
>>
>> It doesn't even seem possible to have more "network connections"
>> by just splicing more Ethernet wires together vs a dumb hub ????
>>
>> I could see if you were trying to split out the tip/ring (4/5) or
>> power (7/8)
>> but an Ethernet splitter ?????

P.Schuman wrote:
> News Reader wrote:
>> I've had splitters like this in my tool box for the past decade, but
>> have not actually implemented them.
>
> ok - that pretty much answers the rest of your points
>
>> Mine, are male on one side, and two female on the other.
>>
>> Imagine that you plugged one into a wall jack at the location of a
>> workstation, and another in the closet where your switch resides.
>>
>> This would support two Ethernet or FastEthernet devices at the
>> workstation location (e.g.: host, and network attached printer).
>
> really - how ?
>
>> Each device would utilize two of the four pairs within the 8-wire
>> (e.g.: Cat 5e) cable.
>
> really - how ?
> considering that each Ethernet device normally expects pins 1/2 and 3/6
> to be used ?
> So, you would have to fabricate a custom cable for each of these
> connections at each end
> and then plug that cable into your cable-sharing RJ45 splitters..
> 1/2 = 1/2
> 3/6 = 3/4
>
> 1/2 = 5/6
> 3/6 = 7/8
>

You do not need to fabricate any custom cables, you just use a standard
straight through cable for each connection. The splitters are used in
pairs, one on each end of a single run of cable.
<http://www.homestead.co.uk/productcategorydetail.aspx?CategoryID=51338&onspec ialoffer=False>

You are overlooking the key point.

The splitter is remapping pin placements.

Pins 1,2,3, and 6 on one of the female jacks are mapped to 1,2,3 and 6
on the male end, as you would expect.

The other female jack maps its pins 1,2,3, 6 to the other two wire pairs
(pins 4,5,7 and 8) on the male end.

Best Regards,
News Reader

P.Schuman wrote:
> News Reader wrote:
>> I've had splitters like this in my tool box for the past decade, but
>> have not actually implemented them.
>
> ok - that pretty much answers the rest of your points
>
>> Mine, are male on one side, and two female on the other.
>>
>> Imagine that you plugged one into a wall jack at the location of a
>> workstation, and another in the closet where your switch resides.
>>
>> This would support two Ethernet or FastEthernet devices at the
>> workstation location (e.g.: host, and network attached printer).
>
> really - how ?
>
>> Each device would utilize two of the four pairs within the 8-wire
>> (e.g.: Cat 5e) cable.
>
> really - how ?
> considering that each Ethernet device normally expects pins 1/2 and 3/6
> to be used ?
> So, you would have to fabricate a custom cable for each of these
> connections at each end
> and then plug that cable into your cable-sharing RJ45 splitters..
> 1/2 = 1/2
> 3/6 = 3/4
>
> 1/2 = 5/6
> 3/6 = 7/8
>
>> This is however, not an appropriate thing to do from a performance
>> standpoint, and should not be standard practice.
>>
>> If you were utilizing GigEthernet, I believe all four pairs are used
>> to support a single device, and therefore splitting would not be an
>> option.
>>
>> Best Regards,
>> News Reader
>>
>> P.Schuman wrote:
>>> happen to run across this thread over on the Ethernet newsgroup -
>>>
>>> Some guy found a RJ45 splitter (2-RJ45 jacks to 1-RJ45 jack)
>>> over on ebay (search RJ45 spliiter) that look like the telco 1-line
>>> 2-line adapters,
>>> but yet this guy (and the ebay description) says these "splitters"
>>> .... Features:
>>> a.. Convert a single RJ45 outlet to two RJ45 sockets easily, point
>>> for more conveniently use
>>>
>>> b.. Increase the number of RJ45 network connections on an RJ45
>>> outlet c.. Compact design, feel free to enjoy your internet surfing
>>>
>>> d.. Expand one RJ 45 outlet into two 8 wire RJ-45 T adapter,
>>> parallel wiring
>>>
>>> e.. Connector: 3 x RJ45 female
>>>
>>> f.. 100% Brand New.
>>>
>>> It doesn't even seem possible to have more "network connections"
>>> by just splicing more Ethernet wires together vs a dumb hub ????
>>>
>>> I could see if you were trying to split out the tip/ring (4/5) or
>>> power (7/8)
>>> but an Ethernet splitter ?????
>
>

P.Schuman wrote:
> happen to run across this thread over on the Ethernet newsgroup -
>
> Some guy found a RJ45 splitter (2-RJ45 jacks to 1-RJ45 jack)
> over on ebay (search RJ45 spliiter) that look like the telco 1-line 2-line
> adapters,
> but yet this guy (and the ebay description) says these "splitters" ....

What he doesn't tell you is that you need TWO of these things.
One at the wall plate and one at the back room hub.

You're better off simply dropping in a small $20 hub at the wall
plate location.

AH HAH -
YES.... IF the description mentions that the pins are re-mapped,
then we have a solution -
BUT only if deployed in pairs.
I used to use them for piggyback of Phone + Ethernet + IBM 3270
on a single 8-wire RJ45 jack installed to each cubicle.

The original thread was basically using ONE of these "splitters"
to just walk up to any RJ45 jack, plug in - and now have TWO jacks and TWO
computers connected.
OR - using a "splitter" to run an Ethernet cable between several computers,
and basically T-connect them - as in the old coax days.

BTW - most of the eBay listings I clicked on made no mention of any
re-mapping,
so they might just be parallel RJ45's or ?? who knows what.

News Reader wrote:
> You are overlooking the key point.
>
> The splitter is remapping pin placements.
>
> Pins 1,2,3, and 6 on one of the female jacks are mapped to 1,2,3 and 6
> on the male end, as you would expect.
>
> The other female jack maps its pins 1,2,3, 6 to the other two wire
> pairs (pins 4,5,7 and 8) on the male end.
>
> Best Regards,
> News Reader
>
> P.Schuman wrote:
>> News Reader wrote:
>>> I've had splitters like this in my tool box for the past decade, but
>>> have not actually implemented them.
>>
>> ok - that pretty much answers the rest of your points
>>
>>> Mine, are male on one side, and two female on the other.
>>>
>>> Imagine that you plugged one into a wall jack at the location of a
>>> workstation, and another in the closet where your switch resides.
>>>
>>> This would support two Ethernet or FastEthernet devices at the
>>> workstation location (e.g.: host, and network attached printer).
>>
>> really - how ?
>>
>>> Each device would utilize two of the four pairs within the 8-wire
>>> (e.g.: Cat 5e) cable.
>>
>> really - how ?
>> considering that each Ethernet device normally expects pins 1/2
>> and 3/6 to be used ?
>> So, you would have to fabricate a custom cable for each of these
>> connections at each end
>> and then plug that cable into your cable-sharing RJ45 splitters..
>> 1/2 = 1/2
>> 3/6 = 3/4
>>
>> 1/2 = 5/6
>> 3/6 = 7/8
>>
>>> This is however, not an appropriate thing to do from a performance
>>> standpoint, and should not be standard practice.
>>>
>>> If you were utilizing GigEthernet, I believe all four pairs are used
>>> to support a single device, and therefore splitting would not be an
>>> option.
>>>
>>> Best Regards,
>>> News Reader
>>>
>>> P.Schuman wrote:
>>>> happen to run across this thread over on the Ethernet newsgroup -
>>>>
>>>> Some guy found a RJ45 splitter (2-RJ45 jacks to 1-RJ45 jack)
>>>> over on ebay (search RJ45 spliiter) that look like the telco 1-line
>>>> 2-line adapters,
>>>> but yet this guy (and the ebay description) says these "splitters"
>>>> .... Features:
>>>> a.. Convert a single RJ45 outlet to two RJ45 sockets easily,
>>>> point for more conveniently use
>>>>
>>>> b.. Increase the number of RJ45 network connections on an RJ45
>>>> outlet c.. Compact design, feel free to enjoy your internet surfing
>>>>
>>>> d.. Expand one RJ 45 outlet into two 8 wire RJ-45 T adapter,
>>>> parallel wiring
>>>>
>>>> e.. Connector: 3 x RJ45 female
>>>>
>>>> f.. 100% Brand New.
>>>>
>>>> It doesn't even seem possible to have more "network connections"
>>>> by just splicing more Ethernet wires together vs a dumb hub ????
>>>>
>>>> I could see if you were trying to split out the tip/ring (4/5) or
>>>> power (7/8)
>>>> but an Ethernet splitter ?????

The seller is not necessarily trying to deceive anyone.

Many products are promoted based on features, without any reference to
how to implement the functionality.

The eBay post was probably like most news posts, incomplete.

Best Regards,
News Reader

P.Schuman wrote:
> AH HAH -
> YES.... IF the description mentions that the pins are re-mapped,
> then we have a solution -
> BUT only if deployed in pairs.
> I used to use them for piggyback of Phone + Ethernet + IBM 3270
> on a single 8-wire RJ45 jack installed to each cubicle.
>
> The original thread was basically using ONE of these "splitters"
> to just walk up to any RJ45 jack, plug in - and now have TWO jacks and TWO
> computers connected.
> OR - using a "splitter" to run an Ethernet cable between several computers,
> and basically T-connect them - as in the old coax days.
>
> BTW - most of the eBay listings I clicked on made no mention of any
> re-mapping,
> so they might just be parallel RJ45's or ?? who knows what.
>
> News Reader wrote:
>> You are overlooking the key point.
>>
>> The splitter is remapping pin placements.
>>
>> Pins 1,2,3, and 6 on one of the female jacks are mapped to 1,2,3 and 6
>> on the male end, as you would expect.
>>
>> The other female jack maps its pins 1,2,3, 6 to the other two wire
>> pairs (pins 4,5,7 and 8) on the male end.
>>
>> Best Regards,
>> News Reader
>>
>> P.Schuman wrote:
>>> News Reader wrote:
>>>> I've had splitters like this in my tool box for the past decade, but
>>>> have not actually implemented them.
>>> ok - that pretty much answers the rest of your points
>>>
>>>> Mine, are male on one side, and two female on the other.
>>>>
>>>> Imagine that you plugged one into a wall jack at the location of a
>>>> workstation, and another in the closet where your switch resides.
>>>>
>>>> This would support two Ethernet or FastEthernet devices at the
>>>> workstation location (e.g.: host, and network attached printer).
>>> really - how ?
>>>
>>>> Each device would utilize two of the four pairs within the 8-wire
>>>> (e.g.: Cat 5e) cable.
>>> really - how ?
>>> considering that each Ethernet device normally expects pins 1/2
>>> and 3/6 to be used ?
>>> So, you would have to fabricate a custom cable for each of these
>>> connections at each end
>>> and then plug that cable into your cable-sharing RJ45 splitters..
>>> 1/2 = 1/2
>>> 3/6 = 3/4
>>>
>>> 1/2 = 5/6
>>> 3/6 = 7/8
>>>
>>>> This is however, not an appropriate thing to do from a performance
>>>> standpoint, and should not be standard practice.
>>>>
>>>> If you were utilizing GigEthernet, I believe all four pairs are used
>>>> to support a single device, and therefore splitting would not be an
>>>> option.
>>>>
>>>> Best Regards,
>>>> News Reader
>>>>
>>>> P.Schuman wrote:
>>>>> happen to run across this thread over on the Ethernet newsgroup -
>>>>>
>>>>> Some guy found a RJ45 splitter (2-RJ45 jacks to 1-RJ45 jack)
>>>>> over on ebay (search RJ45 spliiter) that look like the telco 1-line
>>>>> 2-line adapters,
>>>>> but yet this guy (and the ebay description) says these "splitters"
>>>>> .... Features:
>>>>> a.. Convert a single RJ45 outlet to two RJ45 sockets easily,
>>>>> point for more conveniently use
>>>>>
>>>>> b.. Increase the number of RJ45 network connections on an RJ45
>>>>> outlet c.. Compact design, feel free to enjoy your internet surfing
>>>>>
>>>>> d.. Expand one RJ 45 outlet into two 8 wire RJ-45 T adapter,
>>>>> parallel wiring
>>>>>
>>>>> e.. Connector: 3 x RJ45 female
>>>>>
>>>>> f.. 100% Brand New.
>>>>>
>>>>> It doesn't even seem possible to have more "network connections"
>>>>> by just splicing more Ethernet wires together vs a dumb hub ????
>>>>>
>>>>> I could see if you were trying to split out the tip/ring (4/5) or
>>>>> power (7/8)
>>>>> but an Ethernet splitter ?????
>
>

On Fri, 28 Mar 2008 12:09:53 -0400, News Reader <(E-Mail Removed)>
wrote:

>I've had splitters like this in my tool box for the past decade, but
>have not actually implemented them.
>
>Mine, are male on one side, and two female on the other.
>
>Imagine that you plugged one into a wall jack at the location of a
>workstation, and another in the closet where your switch resides.
>
>This would support two Ethernet or FastEthernet devices at the
>workstation location (e.g.: host, and network attached printer).
>
>Each device would utilize two of the four pairs within the 8-wire (e.g.:
>Cat 5e) cable.
>
>This is however, not an appropriate thing to do from a performance
>standpoint, and should not be standard practice.
>
>If you were utilizing GigEthernet, I believe all four pairs are used to
>support a single device, and therefore splitting would not be an option.
>
>
>Best Regards,
>News Reader
>
>P.Schuman wrote:
>> happen to run across this thread over on the Ethernet newsgroup -
>>
>> Some guy found a RJ45 splitter (2-RJ45 jacks to 1-RJ45 jack)
>> over on ebay (search RJ45 spliiter) that look like the telco 1-line 2-line
>> adapters,
>> but yet this guy (and the ebay description) says these "splitters" ....
>>
>> Features:
>> a.. Convert a single RJ45 outlet to two RJ45 sockets easily, point for
>> more conveniently use
>>
>> b.. Increase the number of RJ45 network connections on an RJ45 outlet
>>
>> c.. Compact design, feel free to enjoy your internet surfing
>>
>> d.. Expand one RJ 45 outlet into two 8 wire RJ-45 T adapter, parallel
>> wiring
>>
>> e.. Connector: 3 x RJ45 female
>>
>> f.. 100% Brand New.
>>
>> It doesn't even seem possible to have more "network connections"
>> by just splicing more Ethernet wires together vs a dumb hub ????
>>
>> I could see if you were trying to split out the tip/ring (4/5) or power
>> (7/8)
>> but an Ethernet splitter ?????
>>

News has the right answer. These splitters break out the 4 pairs into
two sets of two. There is no problem with this in the ethernet
standard (cat 5 can support 2 ethernet lans if they are 10/100)
Don't do this with POTS phones unless you can live with the errors
when the phone rings.
It will not work with gigabit LAN, that needs all 4 pairs.

BTW I am doing this at my house and it works fine. (no packet errors)