View source for E1/T1 Interface ← E1/T1 Interface

== Why not TDMoIP / CESoIP? ==

Usual E1/T1 over IP protocols use generic frames over IP transfer that makes 2 megabits constant rate with up to 8000 packets per second. That approach:
* not suitable for distributed sites with limited internet access
* makes constant parasite load on the servers
* requires delays to compensate jitters
* has issues with asynchronous-to-synchronous transition

Fur such kind of integrations we prefer to have our own agent software on-site with hardware E1/T1 interfaces.
* good timings driven by E1/T1 clock or GPS
* good framing due to synchronous composition on the site
* less traffic due to transfer only valuable demultiplexed information

= icE1usb =

[[Image:IcE1usb-usb side.jpg|300px]]

We have chosen [https://osmocom.org/projects/e1-t1-adapter/wiki/IcE1usb Osmocom icE1usb] as a primary interface for our projects for several reasons:
* good compatibility with big range of hardware hosts due to use USB
* in opposite to most of DAHDI interfaces it is in production
* open-source hardware design
* [https://github.com/osmocom/osmo-e1d open-source user-space driver], no need for the kernel driver
* suitable API for our purposes
* available at [https://sysmocom.de/products/lab/icE1usb/index.html Sysmocom's web shop]

User manual can be found [https://ftp.osmocom.org/docs/latest/icE1usb-usermanual.pdf here].

== Driver installation ==

We maintained [https://osmocom.org/projects/osmo-e1d/wiki Osmocom E1D] in our Debian repository (amd64, arm64). It has no modifications so you can use any source of packages you want or build from the sources.

<pre>sudo apt install osmo-e1d</pre>

== Driver configuration ==

=== /etc/osmocom/osmo-e1d.cfg ===

<pre>
log syslog daemon
e1d
 interface 0 icE1usb
  usb-serial [interface serial number]
  line 0
  line 1
</pre>

More information about logging section can be found [https://ftp.osmocom.org/docs/latest/osmomsc-vty-reference.pdf here], [https://osmocom.org/news/9 here] and [https://gitea.osmocom.org/osmocom/libosmocore/src/branch/master/src/vty/logging_vty.c here].<br/>
(If you care about configuration file format, please check the sources [https://github.com/osmocom/osmo-e1d/blob/97b15ae3970701d20bb35eca771d6ddc87c703af/src/vty.c#L220 here]).

How to find a serial number of connected icE1usb:
<pre>sudo lsusb -d 1d50:6145 -v 2> /dev/null | grep iSerial</pre>

Reload a service:
<pre>sudo systemctl restart osmo-e1d</pre>

You can also test your configuration from the command line:
<pre>sudo osmo-e1d -c /etc/osmocom/osmo-e1d.cfg</pre>

== Issues with the second E1 port ==

''Please note that on many XHCI host controllers there seem to be implementation flaws in the XHCI host controller
firmware preventing the activation of both icE1usb ports simultaneously. The XHCI controller firmware erroneously
claims that there is insufficient bus bandwidth. However, the same icE1usb hardware/firmware works perfectly fine with
OHCI, UHCI and EHCI host controllers. See https://osmocom.org/projects/e1-t1-adapter/wiki/Isochronous_USB_Issues
for a user-maintained list of USB hosts / controllers and whether or not they work with two E1 ports.''