Portable analog modem

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#73489 14-Dec-2010 19:15

Does anyone know a mobile device that you can plug an analog modem into?

We have a need to have an overseas service to dial into a local device (it's not a computer ... just a device) and we can't currently install an analog phone line.

sbiddle

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#417261 14-Dec-2010 21:04

It's not possible.

I saw a GSM fixed terminal many years ago that had a serial port allowing it to be used as a dialup modem using GSM circuit switched data. There are also GSM fixed terminals that support the use of fax machines as GSM has native support for G3 fax

There is nothing however that gives a RJ11 port like a CTU can for voice that will allow the use of a regular low speed data device.

keewee01

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#417365 14-Dec-2010 23:52

They are out there as I have one at work. It is a cellular mobile device that you plug a normal phone into. Branding is Tellular. Orb sell them. You just need a power source, plus your device into it and away you go.

It wasn't cheap - from memory it was around $600!

sbiddle

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#417410 15-Dec-2010 06:15

keewee01: They are out there as I have one at work. It is a cellular mobile device that you plug a normal phone into. Branding is Tellular. Orb sell them. You just need a power source, plus your device into it and away you go.

It wasn't cheap - from memory it was around $600!

CTU's that allow analogue phones exist and are as cheap as chips. As I explained above however these are for analogue phones and are only suitable for voice calling. They will not work with data devices.

Over a mobile connection voice is compressed using a voice codec such as AMR, FR or EFR depending on the network making it impossible to carry modem signals. The GSM adapters that do G3 fax convert the modem signals and use the GSM circuit switched data network to carry the data. XT does not have a legacy circuit switched data network, the only carrier to do so is Vodafone with their GSM network.

keewee01

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#417421 15-Dec-2010 07:39

sbiddle:
keewee01: They are out there as I have one at work. It is a cellular mobile device that you plug a normal phone into. Branding is Tellular. Orb sell them. You just need a power source, plus your device into it and away you go.

It wasn't cheap - from memory it was around $600!

CTU's that allow analogue phones exist and are as cheap as chips. As I explained above however these are for analogue phones and are only suitable for voice calling. They will not work with data devices.

Over a mobile connection voice is compressed using a voice codec such as AMR, FR or EFR depending on the network making it impossible to carry modem signals. The GSM adapters that do G3 fax convert the modem signals and use the GSM circuit switched data network to carry the data. XT does not have a legacy circuit switched data network, the only carrier to do so is Vodafone with their GSM network.

Out Telular was connected to a modem in an alarm panel and would dial out to our head branch from a remote North Island location to report alarm code whenever there were issues with the equipment. Telecom even sold us a very cheep data only plan for it use! So you can understand if I beg to differ.

sbiddle

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#417476 15-Dec-2010 09:46

keewee01:
sbiddle:
keewee01: They are out there as I have one at work. It is a cellular mobile device that you plug a normal phone into. Branding is Tellular. Orb sell them. You just need a power source, plus your device into it and away you go.

It wasn't cheap - from memory it was around $600!

CTU's that allow analogue phones exist and are as cheap as chips. As I explained above however these are for analogue phones and are only suitable for voice calling. They will not work with data devices.

Over a mobile connection voice is compressed using a voice codec such as AMR, FR or EFR depending on the network making it impossible to carry modem signals. The GSM adapters that do G3 fax convert the modem signals and use the GSM circuit switched data network to carry the data. XT does not have a legacy circuit switched data network, the only carrier to do so is Vodafone with their GSM network.

Out Telular was connected to a modem in an alarm panel and would dial out to our head branch from a remote North Island location to report alarm code whenever there were issues with the equipment. Telecom even sold us a very cheep data only plan for it use! So you can understand if I beg to differ.

Data calls and voice calls are two entirely different things. Data calls can't be sent over a voice circuit on a digital mobile network due to the compressed audio codecs that are used vs the ulaw codecs in TDM networks that support modems.

Most alarm panels use a protocol known as ContactID. This is DTMF based and will work with any CTU as it's simply making a voice call and is presumably what your system used. There are 1000's of such units in use in NZ right now in alarm panels.

Circuit Switched Data is entirely different as it doesn't use normal voice channels but sets up a dedicated 9.6k or 14.4k time slot which directly through to the MSC where it's then "converted" back to a analogue signal to interconnect with the PSTN. The XT network doesn't support circuit switched data so the use of any fixed terminals to act as a modem or support G3 fax isn't available

keewee01

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#417524 15-Dec-2010 10:52

sbiddle:
keewee01:
sbiddle:
keewee01: They are out there as I have one at work. It is a cellular mobile device that you plug a normal phone into. Branding is Tellular. Orb sell them. You just need a power source, plus your device into it and away you go.

It wasn't cheap - from memory it was around $600!

CTU's that allow analogue phones exist and are as cheap as chips. As I explained above however these are for analogue phones and are only suitable for voice calling. They will not work with data devices.

Over a mobile connection voice is compressed using a voice codec such as AMR, FR or EFR depending on the network making it impossible to carry modem signals. The GSM adapters that do G3 fax convert the modem signals and use the GSM circuit switched data network to carry the data. XT does not have a legacy circuit switched data network, the only carrier to do so is Vodafone with their GSM network.

Out Telular was connected to a modem in an alarm panel and would dial out to our head branch from a remote North Island location to report alarm code whenever there were issues with the equipment. Telecom even sold us a very cheep data only plan for it use! So you can understand if I beg to differ.

Data calls and voice calls are two entirely different things. Data calls can't be sent over a voice circuit on a digital mobile network due to the compressed audio codecs that are used vs the ulaw codecs in TDM networks that support modems.

Most alarm panels use a protocol known as ContactID. This is DTMF based and will work with any CTU as it's simply making a voice call and is presumably what your system used. There are 1000's of such units in use in NZ right now in alarm panels.

Circuit Switched Data is entirely different as it doesn't use normal voice channels but sets up a dedicated 9.6k or 14.4k time slot which directly through to the MSC where it's then "converted" back to a analogue signal to interconnect with the PSTN. The XT network doesn't support circuit switched data so the use of any fixed terminals to act as a modem or support G3 fax isn't available

Ah, OK. The contract we had with Telecom was a data only contract - no voice. This device was connecting on the CDMA network - NOT the XT Network so I don't know if that is a factor.