Tunnel – Reading meter boxes via 3G in scenarios with an already installed modem that can’t be disconnected (the current modem must be kept)

Scenario details:

• We want to read an electric meter box every 10 minutes. Since the frequency is high, we’ll access the meter box via GPRS/3G instead of with GSM calls to reduce costs
• Simultaneously, the electric company will make a daily conventional GSM data pone call to read the meter box
• In this scenario there’s a company modem already installed, which can’t be disconnected, since the company makes the daily call to their modem SIM. The solution is to install an MTX-3G-Java-T2 modem between the meter box which needs to be read and the company modem

Configuration example (config.txt file) for said scenario:

Configuration

Observations

COMM_baudrate: 9600 COMM_bitsperchar: 8 COMM_autorts: off COMM_autocts: off COMM_stopbits: 1 COMM_parity: none COMM2_baudrate: 9600 COMM2_bitsperchar: 8 COMM2_autorts: off COMM2_autocts: off COMM2_stopbits: 1 COMM2_parity: none GPRS_apn: movistar.es GPRS_login: MOVISTAR GPRS_password: MOVISTAR GPRS_timeout: 0 MTX_mode: server MTX_model: 199801406 MTX_ping: 35 MTX_pingIP: 8.8.8.8 MTX_portAux: bypass TCP_port: 20010 SMS_allPhones: on SMS_sendIP: on SMS_ATEnabled: on SMS_ATResponse: on FIREWALL_enabled: off TELNET_enabled: on TELNET_login: user TELNET_password: 1234 TELNET_port: 20023

Serial port baud rate Number of bits No flow control No flow control 1 stop bit No parity Company’s modem serial port speed Number of data bits No flow control No flow control 1 stop bit configured No parity bit APN GPRS provided by the GSM operator GPRS Login GPRS Password Modem is always GPRS connected GPRS connection server type Modem model Ping time to oversee connection Google IP (f.e.) to ping Gateway between serials with preference Establish the gateway between ports All phones are allowed IP by SMS authorized AT by SMS allowed SMS AT responses activated No firewall Telnet enabled Telnet username Telnet password Telnet TCP port

Details:

• It’s necessary to connect the meter box to the MTX COM1 connector (which is the DB9 connector that’s closer to the MTX modem GSM antenna) and the GSM modem to the MTX COM2 connector
• Remember you may need a crossover cable between the MTX modem and the company’s GSM modem