Batboard

Hello I would like to link a Quantar to a DIU via a wireless link.

The setup would be Quantar -- Blackbox RS-232/Ethernet Converter -- PTP Ethernet Radio -- BlackBox RS-232/Ethernet Converter --DIU

The RS-232/Ethernet Converter manual say it supports serial tunneling over IP which I understand would transparently convert all serial communications over an IP network.

I am having doubts on this config since I read some posts in here about the clock/synchronization --maybe timeouts if the V.24 link uses keepalives??

I will appreciate any feedback &validation on this design.

Thanks!

V.24 is a local link only. The transmit clock is not passed in RS232 converters. Of course, YMMV. It is worth a try if you can set it all up in the shop first to debug problems. The normal setup is to use an AstroTAC 3000 with an astro modem link to the station, and the diu going into port 0.

fortia wrote:Hello I would like to link a Quantar to a DIU via a wireless link.

The setup would be Quantar -- Blackbox RS-232/Ethernet Converter -- PTP Ethernet Radio -- BlackBox RS-232/Ethernet Converter --DIU

The RS-232/Ethernet Converter manual say it supports serial tunneling over IP which I understand would transparently convert all serial communications over an IP network.

I am having doubts on this config since I read some posts in here about the clock/synchronization --maybe timeouts if the V.24 link uses keepalives??

I will appreciate any feedback &validation on this design.

Thanks!

The previous responce is correct. V.24 is 9600 baud synchronous operation (vs asynchronous, where the data stream can be intermittant). A Premisys channel bank (see ebay for these - cheap) (interface is using t1's) can handle this. I don't know if your PTP has T1 carriers, but if it does, then this is the thing for you! The V.24 circuit runs on a Sub Rate Unit serial card (SRU), while the 4 wire audio is put on a 4W E&M card (if your using mixed mode operation - not needed if just CAI P25 operation is being used). The real problem is the data stream - I havent seen much in the way (not to say it doesn exist, I just haven't run across it) of V.24 to ethernet conversion boxes out there. I've even ran (the V.24 data portion) Quantar base stations to a pair of V.24 lease line modems (paradyne 3810's) on dedicated 4 wire circuits some 2000 ft to the DIU's, then into a MCC-5500 console - works great. The Mixed mode audio is on seperate audio pairs between the DIU and Quantars.
B.

Hello.

For this application I have used a PTP, or canopy links with a vanguard 340 with serial tbop port for V24.

I hope this helps you

As previously posted the connection needs to be a 9,600 bps synchronous RS-232 connection.

Obviously your Quantar has to have the appropriate port, if it exits it is on the front of the station on the Control panel but the connector is actually mounted on a daughter board fitted to the wireline card. This RS-232 / V.24 RJ-45 jack has the following pinout:

1 -- RCLK clock to Quantar
2 -- CD input to Quantar
3 -- TCLK clock from Quantar
4 -- GND
5 -- RxD input to Quantar
6 -- TxD from Quantar
7 -- CTS
8 -- RTS

Some Quantars have a modem mounted in this position designed to transport the 9,600 bps over a 4-wire circuit which does not support RS-232.

Note that most Serial to IP over Ethernet converters are not synchronous so they don’t support the RCLK and TCLK signals. What’s worse, those that are synchronous often will not support transporting the TCLK from the Quantar to the remote end of the link (usually a DIU).

The DIU has a DB-25 COMM connector that follows the standard RS-232 pinout:

2 -- TD to Quantar
3 -- RD from Quantar
4 -- RTS to Quantar
5 -- CTS from Quantar
7 -- GND
8 -- CD from Quantar
17 -- RCLK receive clock from Quantar
24 -- TCLK internal TX clock to Quantar

When people hook up to channel banks they often overlook the clocking issue, hence the so called clock slip problem. The channel bank provides a good clock to feed the Quantar RCLK input but unless there is a feature called secondary TX clock you have a problem as the standard channel bank has two clock outputs; one to clock data into the channel bank and one to clock data out of the channel bank RX. We need a clock output and a clock input. I don't think anything from Black Box does this.

There is slightly more configuration flexibility in the DIU as from the CPS you can change the clocking direction of the TCLK lead.

The next issue with Serial to IP over Ethernet converters, such as the IPTube from http://www.engagecom.com which does support synchronous and does properely support separate TX and RX clocks, is the buffer delay. The converter box needs to collect up some bits into an IP packet before they are transmitted. Buffering a small packet, say 256 bytes long, introduces a delay of 0.2 seconds. Note that it is not a matter of how fast the IP link is but simply that to fill a 256 byte buffer at 9,600 bps takes 213 ms. The normal IP MTU is around 1500 byes and at that size the delays is 1.25 seconds!

You need to juggle the packet size to get acceptable latency.

If you want to support mixed mode you need to implement both the V.24 connection and the 4 wire audio connection.

By far the best option is to get one of the wireless products that has a T1 interface option then hook up a channel bank with a V.24 synch card.

Hello, thanks all for your replies!

I tested the RS232/Ethernet converters from BlackBox and they dont support the clocking signals from the V.24 link. So NO luck!

However since my deployment is to have the DIU connected to the Quantar on one side and on the other to a RNC (a data gateway for conventional radios) I am seeing a new solution...what if i moved the DIU to the repeater site to be directly connected to the Quantar and just use the RS232/Ethernet converters to wirelessly remote the link from the RNC to the DIU (this to my knowledege is a RS232 asynchronous connection, not a v.24 synchronous link).

Would that work?

Thanks for all your replies so far! They have been very instructive.

Regards

If you're considering putting the DIU at the repeater site then I guess you're not going to be running secure? You can’t put keyed infrastructure at an insecure remote site.

I’m sorry I don’t understand your system enough to comment further. The DIU converts the IMBE voice to analog so if you did remote it you’d have audio to transport and not data. Maybe I’m missing something.

Astro Modems... oh how they worked so well for this...

tpg

The system is mainly for GPS Vehicle tracking...The mobiles in the vehicles have a GPS; the GPS will send their coordinates trough the Quantar then the DIU then the RNC- WNG and finally to the mapping application.

The repeater site is not very accesible and we have the DIU, RNC, WNG and the mapping application in a central location. The original problem is how to have the QUantar connected remotely to the DIU at the central location.

What I am thinking is moving all the equipment up to the repeater site (with all electrical adecuations we have to do, the repeater site does not have a very stable electrical service). And only the output from the WNG to the mapping application via a wireless point to point link.

HOpe that clears the deployment. Please keep commenting if any one has a better idea.

Regards.

The Pager Geek wrote:Astro Modems... oh how they worked so well for this...

tpg

They are making/selling them again under a different part number.

GEMOTO wrote:

The Pager Geek wrote:Astro Modems... oh how they worked so well for this...

tpg

They are making/selling them again under a different part number.

HPD1000?

escomm

http://batboard.batlabs.com/viewtopic.php?f=10&t=90270

Replacement...

tpg

Hello everybody.

Acording my comment posted before, you must think about Vanguard 340 with serial Sync ports & E&M, is the basic one, I have some Quantars working with secure, in the base station I have Dius, Mcc5500, etc, and as I commented I am using Ethernet PTP links in the midle.

The vanguards I am using have the next ports:

1 Ethernet- connected to the PTP Ethernet link, point to point.
1 Sync serial port to V24 Diu.......V24 Qtr by the other side
1 E&M Four wire port to audio diu port.......Quantar Wireline by the other side if you want analog audio

And thats all.......You have to consider in the vanguards the Serial ports working as a "Tbop Sync port"

I hope this helps.