ZyXEL U-1496P Portable Cellular Modem Summary

ZyXEL U-1496P Portable Cellular Modem Summary

The UNAVCO Boulder Facility has used the ZyXEL U-1496P Portable Cellular Modem, available from ZyXEL (http://www.zyxel.com), in remote communication applications. The cellular modem is used with a Motorola Cellular Phone and a 10dB directional Yagi antenna. The U-1496P is capable of transmission speeds up to 19.2 kbps full-duplex on a 2-wire dial-up line. Universal compatibility covers a broad range of CCITT and Bell standards and provides data compression, asynchronous and synchronous operations, MNP and V.42 error correction and data compression.

Below are the suggested settings of the Zyxel Cellular Phone Modem when directly attached to a Trimble 4000 SSE/SSI receiver and using the Trimble "rfile -f" program. The modem is set at 9600 baud and Zyxel Cell 9600 transfer protocol.

Zyxel settings (when attached to mobile phone):
B0 E1 L2 M1 N5 Q0 V1 X5
&B1 &C1 &D0 &G0 &H3 &J0 &K4 &L0 &M0 &N44 &P0 &R1 &S0 &X0 &Y1 *B0 *C0 *D0 *E0 *F0 *G0 *I0 *L0 *M0 *P9 *Q2 *S0 S00=001   S01=000   S02=043   S03=013   S04=010 S05=008   S06=003   S07=060   S08=002   S09=006 S10=007   S11=070   S12=000   S13=000   S14=003 S15=002   S16=000   S17=018   S18=000   S19=044 S20=007   S21=050   S22=040   S23=105   S24=074 S25=000   S26=000   S27=156   S28=068   S29=000 S30=000   S31=017   S32=019   S33=255   S34=030 S35=032   S36=000   S37=000   S38=000   S39=000 S40=000   S41=000   S42=064   S43=000   S44=000 S45=100   S46=028   S47=064   S48=000   S49=137 S50=002   S51=000   S52=000   S53=000   S54=000 s55=000   S56=000   S57=000   S58=000   S59=000 Receiver set up: BAUD RATE / FORMAT = 9600, 8, NONE, 1, no flow control REMOTE PROTOCOL = DATA COLLECTOR COMPATIBLE Attach the receiver to the remote modem via a null modem cable. Zyxel settings (when installed in office): S49=000

Remote Communications Configurations

If you are interested in more information about how the ZyXEL Cellular Modem is being used by the UNAVCO Boulder Facility in the field select the link below:

Important notes: Optimizing the cellular connection to an acceptable level of data throughput can sometimes be difficult. Local cellular providers may perform operations that are undetectable for voice communication but are incompatible with high speed data transfers. The data communication should be tested by doing a receiver download from a remote site. At certain locations we found the V.32 (4800 bps) protocol (&N5) to work flawlessly while the recommended CELL4800 protocol (&N46) did not work at all or was at best intermittent. Switching the local cellular provider may also improve the cellular reception and thus the data throughput. As with the phone modem, echo should be turned off (E0) at the remote modem to avoid sending data back to the receiver that may cause it to freeze up. DTE/DCE rate is fixed at the DTE setting (see S18, S20, S44b6) to avoid connection at other DTE speeds than what is set in the receiver. We currently use RTS/CTS hardware flow control with our remote communications but no error control or data compression.

Troubleshooting tips:

  • Make sure that the local cellular provider at the remote site is not performing any activities or operations such as multiplexing or data compression that will impact the connectivity and data throughput.

  • To maximize reception the directional antenna must be turned until maximum reception is indicated on the cellular phone handset. Consult the manufacturer manual for details. Note that the direction of the best reception may change if you switch local cellular providers. Also, the directional Yagi antenna has a considerable front- and backlobe which can affect the GPS signal reception if the Yagi antenna is pointed towards (0 deg) or away from (180 deg) the GPS antenna.

  • Longer waiting time for carrier (S7) and longer duration after loss of carrier (S10) before hanging up may increase the chances for a successful connection.

  • The cellular (remote) modem transmit power can be adjusted for maximum reception. But an increased power level can saturate the modem and make it more difficult to make a connection.

  • If repeated calls are being made, allow the modem to disconnect the previous call and reset itself before another attempt is made; or, a separate command should be sent to the local modem to bring the DTR line low if the originating software program does not perform this automatically. This is important when using an automated script to download the receivers. Consult the ZyXEL U-1496 Series User’s Manual for details.

Posted by: - Mon, Sep 21, 2009 at 5:58 PM. This article has been viewed 14894 times.
Online URL: https://kb.unavco.org/kb/article/zyxel-u-1496p-portable-cellular-modem-summary-358.html