Splitting Digital Telephones via Switches (5 to 1)

[Steve21]

Evening All,

 

Now I'll start by saying I think it's impossible unless I'm missing an obvious trick here, but once again SLT never bother to listen when making plans and now want 5 telephones in a room move that doesn't have sockets. (Only 1 spare).

 

We're using an alcatel set that's got all the phones directly plugged into it currently doing PoE etc. So currently 1 port = 1 phone line.

 

I know you could use a splitter for 2 telephones over 1 port (4 cables each), but is there any magic/smart way you could use a switch at the client end and VLAN/split these apart over the one CAT5? My brain is saying something like 5 VLANs at the client end switch (Guess that would need to be PoE to power them), the one uplink cable (original phone line) to another switch, and then the 5 ports back out to the telephone system? Does something like that even exist in the real world?

 

Highly doubt it does if I'm honest, but thought I'd put it out there

 

Thanks,

Steve

[mukz]

Have you tried putting an 8port poe switch in there to do the job? Unless i have not understood clearly/ misreading what you have written. It should work

[jdoyle]

go for a soft phone possibly?

 

IP DECT base station?

[timbo343]

Softphone *would* work however I'm having a new phone system installed and moving over to windows 10 at the same time. I have opted my team to have soft phones and found a massive flaw in MS's software.. Windows 10 does not support VLANs on NICs (https://social.technet.microsoft.com/Forums/en-US/c3e80476-21b3-48fd-a875-52b164660728/windows-10-intel-vlan-creation?forum=win10itpronetworking and https://social.technet.microsoft.com/Forums/windows/en-US/0840138d-a5a3-41f2-a760-1ff2d318ba17/windows-10-vlans?forum=win10itpronetworking).

 

As for the original problem, the 1 port you have make it a member of the phone VLAN (on HP you would untag that port on the particular VLAN) and then put in a small desktop switch (not the best way to do this) connected to this port. That should mean that this switch is only talking on this VLAN and anything after this plugged into this untagged port on the main switch gets only that VLAN. Messy but its the way I would do it and buy some TP-LINK 1Gb PoE injectors. They are about £17 each (depends where you get them from).

Edited August 12, 2016 by timbo343

[Steve21]

The thing is as it's a digital system (not VOIP) there is no phone VLAN etc as each phone has a specific port in the alcatel unit it plugs into (no switches in between a phone and the exchange currently), so wouldn't I need 1 VLAN per phone? so it knows which phone plugs into which port at the phone exchange end?

 

If that is right a little switch wouldn't work as I'd need the VLAN capability on the switch to allow each port a different VLAN :s Unless I'm missing something?

 

Will have to have a look at softphones but think they want to keep their current units currently to keep in line with the rest of the school

 

Thanks,

Steve

[njc235]

Splicecom do a nice little ISDN SIP gateway. I presume you are going to SIP with the new system you mentioned? You could install this then run a mix of digital and VoIP until your new system is commissioned. You might also want to quote Franklin to your SLT Edited August 13, 2016 by njc235
Typo

[Jamman960]

Unfortunately those digital(Tdm) lines can't be connected into switches at all as they're simply receiving signals/ voltages from the pbx and not IP packets/Ethernet frames, much like your normal incoming phone lines, they'll be getting 48v from the pbx but this isn't Poe.

 

If your system isn't too old it may be a hybrid/sip capable in which case you might be able to buy sip licences and compatible sip phones for the job, if it is purely a Tdm system you will need additional cable runs and possibly an additional line card

 

James

 

Is your pbx

[jdoyle]

what's the model of PABX?

 

Any suggestions from your supplier/maintenance company.

[mukz]

Guess i was completely misunderstood what you said! I don't think the segregated VLANs per phone would work either, but no harm in trying it. Stranger things have happened to me before (tv receiving digital signal with no ariel connected!)

[Chris_Cook]

If its a proprietary digital system that only uses 1 pair per phone, you could use one of these at each end of a cat 5 cable:

 

UNBRANDED - ADQ88 - Cat5e 4 Way Ethernet Cable Splitter, RJ45 Male to 4x RJ11 Female | CPC UK

 

That's assuming you have cat5 for your phone port in the office - it would get you 4 phones.

 

If you have more than 1 PC in the room, could you use a small switch for the PCs and free up a cat5 run?

 

Otherwise, you're probably going to have to run more cable to the room.