COM220 OS 4
Updated: 25-09-2007

  1. It is no longer necessary to use the DIP switch settings to configure the modem for use with PakBus dataloggers or mixed-array dataloggers. This was initially used to distinguish between the way the loggers drove the CLK/HS when ME is active. The array based loggers bring CLK/HS HI when ME is active. The CR1000, CR800/CR850, & CR3000 leave CLK/HS LO while ME is active, but then raise CLK/HS when the “ME Pause” occurs. ME connected devices are expected to stop driving the TX line during this period so that an SDC device can communicate during this “ME Pause”. It now works very well whether connected to a mixed-array datalogger or a PakBus datalogger, and with other devices (SDC devices, storage modules, etc)
  2. Added DCD monitoring so that when a call is incoming, no data (from the CS I/O port) is sent to the modem until the CD line is active. At this point, the modem is out of command mode, and it is safe to send its data. Previously, if an incoming call caused the modem to be powered ON, and data was sent to the modem (from the CS I/O port) before the line negotiation was complete, the modem would sometimes not complete the call.
  3. Modified the inactivity timer so that the inactivity counter is only reset if CD is active, indicating being online. Otherwise, the modem is possibly just echoing characters in command mode. Also added inactivity timer reset based on data coming in on CS I/O port (for ME). For all modes (ME or SDC), if CD becomes inactive, the modem is powered OFF.
  4. Added firmware version # to the SDC Info fields.
  5. Added 20 msec delay after sending the initialization string (ATV0X0S0). We found that the modem would sometimes (2/10 times) not accept and execute the first stored command without this delay. If there were no stored commands, there was no problem. This did not affect country codes.