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Tech Notes

Matrix Wireless Operation with Handheld Telephones

Introduction

Matrix Codecs upgraded to software version 6 and higher and all BlueBox codecs are capable of wireless operation by attaching a handheld GSM telephone. This document describes the changes in operation to make this happen. Version 6 has been tested with the following phones:

  • Nokia 7190
  • Nokia 6210
  • Ericsson R380
  • Ericsson T39
  • Siemens S40*

Although it might not be required, there is a new audio codec firmware update available for GSM operation that incorporates a new "GSM 7.5" mode. This has been added to allow operation on GSM networks and phones that won't support the default "GSM 9.6" bitrate. Although the version 6 firmware shows options for this new mode, selection will result in an error if it is selected without the REV6.0 ACM prom installed. Contact Comrex if you are having trouble connecting in "GSM 9.6" mode, and we can send the new ACM prom. The ACM prom is not user programmable.

*Requires "GSM 7.5" operation on non-HSCSD networks.

Connections

The Matrix will be connected to a wireless phone via the data cable designed for the phone. The data cable will be attached to the 9 pin D MP serial port on the side of the portable Matrix (on the rear of the rack Matrix). Because the MP serial port is configured as a DTE (female gender) connector, you will probably need a null modem adapter to connect the data cable to the Matrix. Note this is not a straight-through gender changer, but an adapter that crosses certain pins. This adapter is usually available at computer supply stores. The pinout of the null modem adapter is:

DB-9M DB-9M
1,6 4
2 3
3 2
4 1,6
5 5
7 8
8 7
Pin 9 N/C Pin 9 N/C

Operation

This section describes how a Matrix wireless call will be connected. Normally, one Matrix will be attached to a wireless phone via the MP serial port and data cable. The other Matrix will be connected to an analog telephone line. Either Matrix can be used to initiate a call, and either Matrix should auto-answer the incoming call.

To connect two Matrix via wireless mode, both Matrix must be upgraded to version 6 or higher. This means you must also upgrade the Matrix that will receive the wireless call (via a land-line). With the upgraded firmware, both Matrix should continue to work normally when wireless mode is not engaged.

In order to complete a call, both upgraded Matrix must be set for wireless operation (including the Matrix receiving the call via land-line). If one Matrix is set for normal POTS codec mode, the wireless call will not work.

When version 6 code is installed on a Matrix rack, it will switch automatically to wireless mode when the "Aux" connector on the rear panel is closed. It will revert to normal POTS codec operation when the connector is opened.

Menu Changes

The Matrix manual describes the main menu in POTS codec mode as having the following five options:

  1. Dial
  2. Answ
  3. Test
  4. Config
  5. Store/Fwd

The newer software offers the following options:

  1. Dial
  2. Answ
  3. Test
  4. Config
  5. More

Selecting option 5 offers the following two choices:

  1. Store & Forward
  2. Wireless

Choosing option 1 brings you to the established Store and Forward Menus as described in the Matrix manual. Option 2 puts the Matrix into Wireless Operational Mode. The Matrix will remain in this mode until you configure it to leave this mode.

Wireless status Display

When in Wireless mode, a new status display is presented:

<Phone model or Modem> <Wireless Service>

Press Qdial or Enter

<Phone model or Modem> displays the currently selected wireless phone to be attached to the MP serial port. If the Matrix is to be used as the "land-line" end of a wireless link, this will display "Modem Mode". If the user has adjusted any settings beyond those of the pre-defined phones, this will read "Advanced".

<Wireless Service> Displays the type of wireless service the Matrix is configured for. If the settings have been made using "Advanced" options, this portion is blank.

As an example, this is the status display of a Matrix ready to place a call on the Ericsson R380 phone using 9.6 GSM service

Erics R380 GSM 9.6
Press Enter or Qdial

This is the display of a Matrix ready to receive a "land-line" call from a GSM 9.6 phone

Modem Mode GSM 9.6
Press Enter or Qdial

Wireless Qdial

Once configured correctly, the Qdial function works the same way as in POTS codec mode. If the Matrix is set for wireless phone operation, the Qdial number will be dialed via the MP serial port to the wireless phone. If the Matrix is set for internal modem operation, the number will be dialed by the internal modem. Use the POTS codec mode menus to program your Qdial locations.

Wireless Menus

When you press <Enter> from the Wireless status display, you will see the main wireless menu:

  1. Dial
  2. Setup
  3. Leave Wireless Mode

Option 1 allows you to manually enter and dial a call via the wireless phone or internal modem, whichever is active on the status display. Option 2 allows you to select whether the MP serial port or the internal modem is active, and allows you to configure each (discussed in the next section). Option 3 will end wireless mode and return to the Pots Codec status display

Setup

When you select Setup, from the main menu, you will be prompted to choose whether this Matrix will be connected to a wireless phone, or will be connected to a land-based phone line (to receive a call from a wireless phone):

  1. Use Wireless Phone
  2. Use internal Modem

After you make a choice, the Matrix will display:

  • Selection
  • Stored

The Matrix will remain in the chosen mode until you change it.

If you choose the "Internal Modem" selection, it is assumed that this Matrix will be connected to a land-based telephone line and that a call will be established in conjunction with a Matrix set for "Wireless Phone" operation on the other end. Once this selection is made, the following menu appears:

  1. Service
  2. V42

Select option 1 to choose the type of wireless service that the Matrix will be using. This is important for the Matrix to know, even though it's only connecting via the land-line. The following options appear:

  1. GSM 9.6
  2. GSM 14.4
  3. GSM 19.2
  4. GSM 28.8

If you don't have GSM HSCSD (High Speed Circuit Switched Data) available both in your network and in your phone, you should select option 1. Otherwise, choose the type of HSCSD you'd like to use.

After choosing an option, it will be stored and echoed to the status display.

Option 2 in the Modem setup menu is for V.42 operation:

  1. V42 on (default)
  2. V42 off

Under normal circumstances, this shouldn't be altered. This option determines how the internal modem connects with the modem within the wireless network. If V.42 is selected (as the default) then V.42 framing and error correction are used, providing a higher throughput. V.42 error correction can cause operational problems on bad lines, so it is possible to disable it and use a lower throughput protocol. Note: Some GSM providers may fail to connect to modems with V.42 disabled.

Back to the main setup menu:

  1. Use Wireless Phone
  2. Use internal Modem

If you choose option 1, a new menu will appear allowing you to choose your phone and service:

  1. Phone/Service
  2. Advanced

Option 1 allows you to select the model of phone you are using. It currently has these options:

  1. 6210
  2. 7190
  3. R380
  4. S40

More will be added as phones can be tested. Make sure the phone is connected to the MP serial port and is powered up, then make your selection.

Once you choose a phone, the next menu will prompt you to choose the GSM service you'll be operating on. If your phone supports HSCSD, you'll see:

  1. 9.6
  2. 14.4
  3. 19.2
  4. 28.8
  5. 7.5

If you don't have GSM HSCSD (High Speed Circuit Switched Data) available both in your network and in your phone, you should select option 1. Otherwise, choose the type of HSCSD you'd like to use. If your phone doesn't support HSCSD, you'll see only the 9.6 and 7.5 options. Make sure your phone is powered up and connected to the Matrix when you choose, or you will get an error message.

After choosing an option, it will be stored and echoed to the status display.

Option 2 allows you to set baud rate, throughput, and init string to values that aren't available in the main setup procedure. Contact Comrex for more information about these settings.