I checked the FAQ, and couldn't find any specifics about how this line works. Then I searched the forum and found some interesting stuff related to hooking up a Nokia phone, posted by jheathco.

I just got one of those Handspring Treo cell phone/pda units, and I am going to get another headset and take it apart to create an AUX adapter. I would like to have the headset trigger the cell mute line, but I have no idea what signal to apply to this line in order to turn on the mute function. After the phone triggers the mute, I am going to use Hijack to switch over to the AUX input just like everyone else seems to be doing. My guess, based on a few comments in the forums, is that the cell mute line is triggered when 12V is applied to it. If that's the case I can either use some signal from the headset to trigger it, or I can simply wire a switch that applies 12V to the cell mute line from the power line.

Does this sound like the right approach, or am I missing something important? Do any of you guys using the empeg as a speakerphone see problems with feedback?

Usually you would be using a car docking adapter specific to that model of cell phone. The car docking adapter would contain the necessary mute wire.

If you don't have the mute wire already sitting there waiting for you to use it, then you're going to have to come up with a clever hack of some kind. The empeg doesn't care, it just responds to the presence of the voltage (or lack of voltage) on the mute line (configurable in emplode).

Sorry for the OT, but how do you like the Treo? It is about time for a new cell phone and I would love to get one with a built in PDA.

-Mike

trust me you dont want the treo, its going to be on a new network called voicestream, sound good uh? nope! well you knwo how bad cingluars service is, droped calls, busy, ect. well voicestream is going to be piggy backing on cigular, it will be loads of fun to own one of those.

I got the Treo about 4 weeks ago through the Handspring web site. I had been planning to get a PDA, but I really didn't want to carry around two electronic devices in my pockets. I figured the the Treo would save me the trouble of carrying around both a cell and a PDA. I got the unit for $399 with Cingular access. When I bought it, they only offered a Cingular deal, but they now offer Voicestream as well. The Treo is quite small for a PDA and a bit large for a cell phone, and it fits in the front pocket nicely.

I have seen a few complaints about Cingular on various Treo-oriented sites, and can't see what the fuss is about. I have driven all over L.A. and all the way up to Napa, CA so far, with no reception or connection problems whatsoever. The only complaints I have are:

-The phone, even at max volume, is a bit weak. It also has echo problems periodically when I use the speaker phone.

-The battery life is pretty short. This is especially noticeable when you use the PDA often.

On the other hand, the PDA has decent memory (16 megs), and the seamless integration between the contacts list in the PDA, the cell apps, and the PC I sync with is great. I haven't had a dropped call or busy network since I started using the phone, and I commute regularly straight through Los Angeles from Pasadena to Irvine (about 50-60 miles, 80-100 km). Of course, I don't know anything about the quality of Cingular access anywhere else.

Anyway...back to the original question: in order to trigger the cell mute line, what do I have to do? Is it as simple as applying 12V to the cell mute wire?

Can't the Treo use normal GSM1900?

Marius (Escort Cab + Mark II)

According to this page,
http://www.handspring.com/products/treo/details.jhtml?sub_nav_section=Details&prod_cat_name=Treo
the Treo can use normal GSM1900.

Ok, one more attempt at getting some real info: what signal does the cell mute input line coming out of the empeg cage look for!?

I did some searching, and found these tidbits:

"Some kits such as the Nokia support stereo muting; this is standardized as a ground sensing circuit. To work, a stereo headunit that supports this mutes when a signal wire is grounded; a handsfree carkit that supports this feature will ground a signal wire when a call is connected."
http://www.audiworld.com/tech/elec12.shtml

"We were fortunate in that our choice of aftermarket deck permitted a connection of the Blue/White mute output of the STARMOD1 to the Stereo Mute input wire of the deck. This meant that when the OnStar system activates, the deck automatically mutes. Some aftermarket components require a connection to chassis ground for muting. In this case, simply use a relay or transistor to convert the STARMOD1's +12 volts into a ground for muting."
http://www.carsound.com/columns/navone/nav0010.shtml

I am going to go tear open my dash one more time and ground the cell mute line while the empeg is playing. Hopefully this will mute the output.

VoiceStream and Cingular are two completely different companies/entities/networks. Sure, they both do GSM 1900, but that's it. Where you live or use the phone will dictate whose network you're using. There are surely some areas where both VoiceStream and Cingular are licensed, and in those areas, you're on on whoever's network you signed up with.

So, whether or not Cingular is any good has no bearing on whether or not VoiceStream is any good. Also, that's nothing specific about the Treo either. Plenty of people used phones with VoiceStream (and Cingular) long before the Treo came around.

If your point is that a purchaser of a Treo has to use it on a GSM1900 network and Cingular and VoiceStream both suck (which may or may not be true), then the Treo does come at a disadvantage since Handspring only activates it with a VoiceStream or Cingular service plan. However, there are other GSM1900 carriers in the US, and a simple SIM card swap will make the Treo work with them. Presumably Handspring will offer other carriers' plans eventually.

(OBTWIAVBP: Discussions of GSM900 and GSM1800 (both of which the Treo also does), and the rest of the world outside the US is completely elminated from this discussion for the sake of brevity)

I'm sure this is in the FAQ but tony doesn't seem to be around to point you to the right question. Anyways, the ansewer is right in front of you I'm afraid. Fire up emplode and check out the player config option. You can chose if it mutes on +0 or +12 volts, so it's up to you how you want it to work.

Matthew

interesting, becuase i sell cingular at my store in corte madera, and the cigular rep told us that voicestream buys the useage from cigular. and i get nothing but troulbe from cigular i sell a phone and 2 days later i get the customer back returing it and switching to either sprint or att.

Ok, one more attempt at getting some real info

Hey, just wanted to apologize for diverting your thread and thanks you for the quick treo review. As someone else mentioned it looks like you can choose ground or +12 from emplode.

As far as the treo and cingular I ordered one yesterday and am really looking forward to getting it. Cingular may not have the best service but most people I know seem to use it without to many complaints.

-Mike

It's possible that in your area, VoiceStream may still want a market presence, but not have a spectrum license to broadcast. In that case, they might be essentially reselling the Cingular network in that area.

I used to know a website where one could figure out exactly who owned the PCS spectrum licenses for a given area, but I can't seem to find it now...

As a side note to the setting in emplode:
I had to put a pull-down resistor between the mute line and ground to make the muting work in my car. It basically looked like this afterwards:

ground ------------+-----------

                   |

               resistor

                   |

mute line ---------+----------- empeg mute input

with a 10kOhm resistor, it worked perfectly (even though a 1kOhm resistor did also work, I tend to use as big resistors as possible for pullup/pulldown purposes, to minimize the current drain they produce).
Edit:If your handsfree set does a pull to ground to do the muting, you need to replace the "pulldown to ground" resistor with a "pullup to 12V" resistor. In other words, just take the above diagram and replace "ground" with "12V" and you are doing the right thing.

cu,
sven

ISTR this is only necessary on a mk2. The mk2a had this resistor internally. Might be imagining things though.

Hugo

Now that you mention it, ISTR the very same thing.
However, even with the MkII, some handfree kits worked without that resistor (probably because they had the resistor internally themselfs). My advice is to try wether the phone mute works without a resistor, and only if it doesn't, add the appropriate resistor.

cu,
sven

Thanks for the help guys. I never thought to check the player config, hehe, since I haven't messed with it for a while now. It makes sense, given the incredible configurability of the empeg, that it would let you decide how to trigger the mute.

I played around with the Treo headset yesterday, and I found that the speaker is completely dead while the phone is ringing. It only activates once I press the single button on the microphone pod. The plug that fits into the Treo looks to be a standard 2.5 mm headset jack, but it has 4 (?) connections on the plug. All the other headsets I've seen have 3 conductors: one for headphone, one for mic, and one for ground. I already ordered another headset, and I plan on taking it apart to see if I can somehow trigger the cell mute line automatically when the phone rings. It looks like I'll have to hack together my own hands-free car adapter, or just mount a switch somewhere to make the phone think it's off the hook.

its going to be on a new network called voicestream

Voicestream is definitly not a new company. They are a GSM provider, much like the rest of the world and have been around for a long time in smaller markets. Colorado has been one of their bigger places, and service here is great. To me, they were better then USWest, so my cell phone became my only phone years ago. Their rates have always been better then the competitors here in the US, and I have a feeling part of that is due to not needing to develop an entire system like CDMA.

GSM is the only way I will go. SIM cards, good digital connections, and the best selection of phones.

Cingular (They were PacBell once wen't they?) also uses GSM on the same 1900 frequency. AT&T is also rumored to be using GSM now as well, so hopefully soon the US will see the death of non-standard cell phone networks.