SPA112 Doesn't Detect Off Hook & No Dial Tone

[David Bosiljevac]

Hi All,

I'm hoping somebody can help me here.  I have an SPA112 telephone adapter that gives me problems with the phone not going off hook to give me a dialtone.

I upgraded the firmware to 1.3.5p recently, thinking this might fix the issue.  It didn't, however, the only time I would be able to go off hook and make phone calls was if I tried to downgrade the firmware and the TA rebooted itself.  Only then could I make and receive calls.  If I reboot the TA after that, it stops working again.

The TA is registering fine with my provider.  The power and phone lights are solid green.  The network light blinks with activity.  When I call the number that I have associated on the line and I look at the status page of the TA, it will say that the phone is ringing.  However, picking the handset up doesn't get detected.

I've tried both line 1 and line 2 and get the same issue.

I'm at my wits end with this.  I'm hoping somebody might have some suggestions here to help me out.

Thanks,

Dave

[Dan Lukes]

Verify line's "Hook State". What's the value shown here when the phone is off-hook ?

How your phone is connected to SPA112 (e.g. wire type/diameter and overall length) ? The type of phone connected ? Is it the old gold mechanic phone, or is it and electronic device ? If electronic - is powered from phone line only ?

At the time the status page claim ringing line - is the phone ringing ?

Did you tried other phone (better "other type" than "other piece" ) ?

Turn on syslog & debug messages and catch them. They may disclose valuable information related to issue.

[David Bosiljevac]

Hi Dan,

When the phone is off the hook, the hook state says "on".

I've tried two different phones - a cordless and corded.  Both attached via regular RJ11.  The corded is powered from the phone line, whereas the cordless is powered with an external source.  The corded phone has worked when the firmware downgrade failed and the TA restarted itself.  A second reboot of the TA after a failed firmware downgrade breaks it again so that the phone doesn't work.

When the line is ringing, you can see it say "ringing" and the caller ID at the other end.

As I've mentioned, I tried two different types of phones.  Both don't work.

I've turned on debugging on the log to see if that shows me anything.

Any thoughts?

Thanks.

[Dan Lukes]

Well, I'm not sure you're familiar with POTS line principles, so I will explain it in short. Analog line is powered from switch side. SPA112 use 48V=

Phone in on-hook state have high impedance and drain almost no current from line.

Phone in off-hook state have low impedance, so it drain current from line.

SPA112 measure the current, so it can detect phone's hook state.

If hook state says "on" even with seized line, it mean

1. broken phone, so high impedance even off-hook.
2. line loop (e.g. wire from SPA112 to phone) have so high impedance itself - e.g. line loop is so long, wire is so thin, wire is damaged (cut or almost cut), problem with connector on an end of line. Note the overall impedance of line loop should not exceed 1000Ohm.
3. broken SLIC chip or line plug in SPA112 - it can't detect current flow correctly, thus it doesn't recognize seized line properly

As you tried more than one phone, we can forget [1].

Connect phone to SPA112 using other short cable. Or better, just short wire 2 & 3 inside of  SPA112's line plug. Don't use so much force as it may damage plug's contact. Note that short contact will not damage the neither device nor you, so don't hesitate.

If "Hook state" remain "On" (don't forged to refresh the page) even with short contact (or off-hook connected with short undamaged line loop) we can be almost sure the SPA112 is damaged. Return it to seller if under warranty. If Hook state become Off with short on line plug, then SPA112 seems to be in good shape and the issue is caused by line loop wire itself (or end connectors).

Syslog & debug will not help here.