1st call not ringing, subsequent calls ringing


Hey all,

Having a strange issue.
Our setup is as follows: We are using 2 Grandstream UCM 6510 with HA, and 3 Grandstream GXW 4248 Gateways in a healthcare facility with 120 rooms (Besides for a number IP phones in the business area of the building).

Two rooms, both connected to the same gateway, are experience the following issue.
When receiving inbound calls, the caller will hear the phone ringing. The physical phone will not ring. If you pick up the phone, you can pickup the call. This only happens the first time. Call back again, and it will ring in the room. All subsequent call will ring.
Wait a couple of hours and this cycle repeats itself.

No other complaints from other rooms. Updated gateway firmware, rebooted several times, re-terminated cables, replaced phones… Can’t get to the bottom of this. Any help would be appreciated.

I found a similar post with no solution.


Are the 2 FXS ports related in the first 8 ports or are they port 1 and 9 or something like that?

Im thinking that you might be experiencing a ring voltage issue or some form of loading on the circuit - is it on new cabling ? is there a short circuit to earth or something like that ?


Smart idea. I’ll go down there and check it out. Keep you posted.


OK… @scottsip looks like you nailed it. I went down to the location yesterday. They had a list of approx 7 rooms that wouldn’t ring on the first try but would ring on try number 2. I noticed a pattern that all affected rooms were at the end of hallways. Except for one room that was right in middle. That room had a splitter with two phones connected :slight_smile:

Question is, how to resolve. If I use a phone with an AC adapter, does that replace the voltage being sent from the gateway? Any other recommendations?


P.S. I tested the voltage and got a reading of 46V in all rooms


Foggy Flu brain… thinking IP sorry Izzy

Remove the splitter and replace the splitter with a poe switch of some form…


Or if you can, install another cable… but I think the POE switch will be a cheaper option… it should be a third of the cost of a cable installation.


I removed the splitter. They don’t need two phones. Any ideas for dealing with the long hallways and apparent power shortage from the gateways to the rooms?


This is what happens when kevs brain is clouded with the flu …

What sort of POE switch do you have brand and model ?


No POE. They have a Grandstream GXW4248 with analog phones. Specifically Cetis Daimond


foggy brain from the flu… forgot all about it and was thinking IP Handsets sorry…

Okay If i remember right the current from the GXW and voltage is or around 46 volts dc with a superimposed ring over the top… you might be having a problem with the current to certain areas… perhaps doubling the pairs to reduce the resistance might prove substantial in fixing the long run cabling resistance load issue…

Check the bottom of the phone and verify the REN of it using the following info… as it might be an older phone…

For products approved after July 23, 2001, the REN for this product is a part of the product identifier that has the format US:AAAEQ##TXXXX. The digits represented by ## are the REN without a decimal point (e.g., 03 is a REN of 0.3). For earlier products, the REN is separately shown on the label.


Just found a spec manual for the handsets…
Ringer Equivalence: - Z

So I looked it up and noted the following:


So I am right it is resistance or impedance matching issue… you have to lower the resistance of the cabling as best as possible or change out the affected handsets with an ren that suits.


How far are the rooms/phones from the gateway? What type and gauge of wire?
The GXW is rated as:
Short Haul 2 REN, up to 6000ft on 24 AWG wire

The ring voltage is 50V (balanced)

Are the premise wires all brought back to the main cross-connect/MDF (GXW location) or do they have closets in the building with intermediate cross connect/IDF blocks? If you move a phone temporarily into the IDF location, does the issue persist? Maybe replacing the wire from the IDF to the phone is an option; otherwise you may be looking at a ring booster. These run around $150/ea for a single line and are available from Viking, Sandman?phoneman and others.

I use Teledex Diamond (and other) series in a number of hotels and the runs are quite long (and some very old) and do traverse IDFs along the way and have had no issue (so far). I was in a hotel yesterday built in 1957 and still using wood blocks and runs in excess of 600 feet with no issue (other than brittle wires).